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Farmus L, Till C, Green R, Hornung R, Martinez-Mier EA, Ayotte P, Muckle G, Lanphear B, Flora D. Critical windows of fluoride neurotoxicity in Canadian children by Farmus and colleagues - In reply to Guichon et al. (2022). ENVIRONMENTAL RESEARCH 2024; 254:115201. [PMID: 36709871 DOI: 10.1016/j.envres.2022.115201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 12/30/2022] [Indexed: 06/18/2023]
Affiliation(s)
- Linda Farmus
- Department of Psychology, York University, Toronto, Canada
| | - Christine Till
- Department of Psychology, York University, Toronto, Canada
| | - Rivka Green
- Department of Psychology, York University, Toronto, Canada
| | - Richard Hornung
- Consultant to Psychology Department, York University, Toronto, ON, Canada
| | | | - Pierre Ayotte
- Department of Social and Preventive Medicine, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | - Gina Muckle
- Centre de Recherche Du CHU de Québec, Université Laval, School of Psychology, Université Laval, Québec, QC, Canada
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, Vancouver, Canada
| | - David Flora
- Department of Psychology, York University, Toronto, Canada
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2
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Guichon J, Nicolau B, Brandini M, Caron C, Mitchell I, D'Souza V. Letter to the editor regarding "Critical windows of fluoride neurotoxicity in Canadian children" by Farmus and colleagues. Environmental research, 111315. https://doi.org/10.1016/j.envres.2021.111315. No fluoride neurotoxicity in Canadian children. ENVIRONMENTAL RESEARCH 2024; 254:115232. [PMID: 36693466 DOI: 10.1016/j.envres.2023.115232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/12/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Affiliation(s)
- Juliet Guichon
- Community Health Sciences and Pediatrics, University of Calgary, Calgary, Alberta, Canada.
| | - Belinda Nicolau
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montréal, Quebec, Canada
| | - Mario Brandini
- Faculty of Dentistry, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christian Caron
- Faculté de Médecine Dentaire, Université Laval, Québec, Canada
| | - Ian Mitchell
- Alberta Children's Hospital, Calgary, Alberta, Canada
| | - Violet D'Souza
- Department of Dental Clinical Sciences, Faculty of Dentistry, Dalhousie University, Halifax, Nova Scotia, Canada
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Alejandro-Vega S, Hardisson A, Rubio C, Gutiérrez ÁJ, Jaudenes-Marrero JR, Paz-Montelongo S. Soft Drinks as a Dietary Source of Fluoride Exposure. Biol Trace Elem Res 2024; 202:3816-3828. [PMID: 37922070 DOI: 10.1007/s12011-023-03937-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/24/2023] [Indexed: 11/05/2023]
Abstract
High fluoride exposures can lead to adverse effects such as dental and bone fluorosis, as well as endocrine and cognitive developmental problems. Water is the main dietary source of this ion, although significant concentrations have also been detected in other beverages widely consumed by the population such as soft drinks. A total of 200 soft drink samples (60 flavoured, 70 extracts, 60 fruit juice and 10 soft drinks) were analysed by fluoride ion selective potentiometry. A consumption of 330 mL was estimated for exposure assessment and subsequent F-risk assessment by soft drink consumption. The highest average concentration was found in extract soft drinks (2.45 ± 1.15 mg/L), followed by flavoured (1.71 ± 2.29 mg/L) and carbonated soft drinks (1.38 ± 0.40 mg/L), while the lowest was found in fruit juice soft drinks (1.09 ± 0.62 mg/L). The flavours with the highest concentration were tea-melon and tea-passion fruit with 3.66 ± 0.40 and 3.17 ± 0.56 mg/L respectively and the lowest was lemon flavour with 0.69 mg/L. The contribution of these beverages, considering the UL (Upper level) reference values set by EFSA (European Food Safety Authority) are between 3.28-41.78%, depending on age group and sex.
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Affiliation(s)
- Samuel Alejandro-Vega
- Area of Toxicology, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
- Grupo interuniversitario de Toxicología Ambiental y Seguridad de los Alimentos y Medicamentos, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
| | - Arturo Hardisson
- Area of Toxicology, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
- Grupo interuniversitario de Toxicología Ambiental y Seguridad de los Alimentos y Medicamentos, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
| | - Carmen Rubio
- Area of Toxicology, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
- Grupo interuniversitario de Toxicología Ambiental y Seguridad de los Alimentos y Medicamentos, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
| | - Ángel J Gutiérrez
- Area of Toxicology, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
- Grupo interuniversitario de Toxicología Ambiental y Seguridad de los Alimentos y Medicamentos, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
| | - Juan R Jaudenes-Marrero
- Area of Toxicology, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
- Grupo interuniversitario de Toxicología Ambiental y Seguridad de los Alimentos y Medicamentos, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain
| | - Soraya Paz-Montelongo
- Area of Toxicology, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain.
- Grupo interuniversitario de Toxicología Ambiental y Seguridad de los Alimentos y Medicamentos, Universidad de La Laguna, Canary Islands, 38071, La Laguna, Tenerife, Spain.
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Wood C. Letter to the editor regarding critical windows of fluoride neurotoxicity in Canadian children by Farmus, L., and colleagues (2021). Environmental Research, 2021;200;111315. https://doi.org/10.1016/j.envres.2021.111315. ENVIRONMENTAL RESEARCH 2024; 254:115202. [PMID: 36709024 DOI: 10.1016/j.envres.2022.115202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 12/12/2022] [Accepted: 12/30/2022] [Indexed: 06/18/2023]
Affiliation(s)
- Christine Wood
- Association of State and Territorial Dental Directors, 3858 Cashill Blvd. Reno, NV, 89509, USA.
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5
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Guichon JR, Cooper C, Rugg-Gunn A, Dickinson JA. Flawed MIREC fluoride and intelligence quotient publications: A failed attempt to undermine community water fluoridation. Community Dent Oral Epidemiol 2024; 52:365-374. [PMID: 38525812 DOI: 10.1111/cdoe.12954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/23/2023] [Accepted: 02/15/2024] [Indexed: 03/26/2024]
Abstract
OBJECTIVE To assess the evidence presented in a set of articles that use the Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study database to claim that community water fluoridation (CWF) is associated with harm to foetal and infant cognitive development. METHODS Critical appraisal of measurements and processes in the MIREC database, and articles derived therefrom. MIREC's cohort is approximately 2000 pregnant women recruited in 10 centres across Canada, 2008-2011, leading to measuring 512 children aged 3-6 years in six cities. Fluoride exposure was measured by city fluoridation status, self-reports and maternal spot urine samples. Intelligence Quotient (IQ) was measured using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-III) by different assessors in each city. RESULTS MIREC's fluoride and IQ measurements are invalid and therefore cannot support the claim that CWF is associated with IQ decline in children. CONCLUSIONS The MIREC fluoride-IQ articles' results should be considered unacceptable for legal and policy purposes; other water fluoridation studies and systematic reviews show no effect of fluoridation on cognition.
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Affiliation(s)
- Juliet R Guichon
- Department of Community Health Sciences and Pediatrics, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Colin Cooper
- School of Psychology, Queen's University, Belfast, UK
| | - Andrew Rugg-Gunn
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - James A Dickinson
- Department of Family Medicine and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Wang R, Gong W, Jiang Y, Yin Q, Wang Z, Wu J, Zhang M, Li M, Liu Y, Wang J, Chen Y, Ji Y. Fluoride exposure during puberty induces testicular impairment via ER stress-triggered apoptosis in mice. Food Chem Toxicol 2024; 189:114773. [PMID: 38823497 DOI: 10.1016/j.fct.2024.114773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 05/15/2024] [Accepted: 05/28/2024] [Indexed: 06/03/2024]
Abstract
Fluoride, a ubiquitous environmental compound, carries significant health risks at excessive levels. This study investigated the reproductive toxicity of fluoride exposure during puberty in mice, focusing on its impact on testicular development, spermatogenesis, and underlying mechanisms. The results showed that fluoride exposure during puberty impaired testicular structure, induced germ cell apoptosis, and reduced sperm counts in mice. Additionally, the SOD activity and GSH content were significantly decreased, while MDA content was significantly elevated in the NaF group. Immunohistochemistry showed an increase in the number of cells positive for GRP78, a key ER stress marker. Moreover, qRT-PCR and Western blot analyses confirmed the upregulation of both Grp78 mRNA and protein expression, as well as increased mRNA expression of other ER stress-associated genes (Grp94, chop, Atf6, Atf4, and Xbp1) and enhanced protein expression of phosphorylated PERK, IRE1α, eIF2α, JNK, XBP-1, ATF-6α, ATF-4, and CHOP. In conclusion, our findings demonstrate that fluoride exposure during puberty impairs testicular structure, induces germ cell apoptosis, and reduces sperm counts in mice. ER stress may participate in testicular cell apoptosis, and contribute to the testicular damage and decreased sperm counts induced by fluoride.
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Affiliation(s)
- Rong Wang
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China; School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China
| | - Wenjing Gong
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Yumeng Jiang
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Qizi Yin
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Ziyue Wang
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Jie Wu
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Mingming Zhang
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Mengyuan Li
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Yehao Liu
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China
| | - Juan Wang
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China.
| | - Yuanhua Chen
- School of Basic Medical Sciences, Anhui Medical University, Hefei, Anhui, China.
| | - Yanli Ji
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, Hefei, Anhui, China; Anhui Provincial Key Laboratory of Population Health and Aristogenics, Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei Anhui, China.
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7
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Moore D, Glenny AM. Fluoride and children's IQ: evidence of causation lacking. Evid Based Dent 2024; 25:95-97. [PMID: 38824186 PMCID: PMC11213703 DOI: 10.1038/s41432-024-01022-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Accepted: 04/15/2024] [Indexed: 06/03/2024]
Abstract
DATA SOURCES Human, animal, and in vitro studies. Extensive literature search of multiple bibliographic databases, trial registries, major grey literature sources and bibliographies of identified studies. STUDY SELECTION The authors aimed to identify studies which could be used to determine the maximum safe level for fluoride in drinking water. To identify new studies published since a 2016 Australian review, the search period was 2016 to July 2021. Studies which evaluated the association between either naturally or artificially fluoridated water (any concentration) and any health outcomes were included. No restrictions on study design or publication status. Articles published in a 'non-Latin language' were excluded. Screening of abstracts and full texts was in duplicate. For IQ and dental fluorosis, a top-up search was conducted between 2021 and Feb 2023. DATA EXTRACTION AND SYNTHESIS Extensive data extraction. Risk of bias assessment using the OHAT tool. A narrative synthesis of the results was carried out. RESULTS The review included 89 studies in humans, 199 in animals and 10 reviews of in vitro studies. Where there was consistent evidence of a positive association, in relation to a water fluoride concentration of <20 ppm (mg F/L), and where studies were judged to be acceptable or high quality, health effects were taken forwards for further examination of causality using Bradford Hill's 9 criteria. Of the 39 health outcomes reviewed, 4 were further assessed for causality. The authors reported 'strong' evidence of causality for dental fluorosis and reductions in children's IQ scores, 'moderate' strength evidence for thyroid dysfunction, 'weak' for kidney dysfunction, and 'limited' evidence for sex hormone disruption. CONCLUSIONS The authors conclude that moderate dental fluorosis and reductions in children's IQ scores are the most appropriate health outcomes to use when setting an upper safe level of fluoride in drinking water. For reductions in children's IQ, the authors acknowledge a biological mechanism of action has not been elucidated, and the dose response curve is not clear at lower concentrations, limiting the ability to set an upper safe threshold.
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Affiliation(s)
- Deborah Moore
- Senior Clinical Lecturer / Honorary Consultant in Dental Public Health, The University of Liverpool, Liverpool, UK.
| | - Anne-Marie Glenny
- Professor of Health Sciences Research, The University of Manchester, Manchester, UK
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Tuomivaara ST, Goin DE, Fisher SJ, Hall SC, Mattis AN, Den Besten PK. Fluoride-related changes in the fetal cord blood proteome; a pilot study. RESEARCH SQUARE 2024:rs.3.rs-3995767. [PMID: 38464284 PMCID: PMC10925477 DOI: 10.21203/rs.3.rs-3995767/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Background Fluoride exposure during pregnancy has been associated with various effects on offspring, including changes in behavior and IQ. To provide clues to possible mechanisms by which fluoride affects human fetal development, we completed proteomic analyses of cord blood serum collected from second-trimester pregnant women residing in Northern California with either high or low fluoride exposure, as identified by maternal serum fluoride concentrations. Objective To identify changes in cord blood proteins associated with maternal serum fluoride concentration in pregnant women living in Northern California. Methods The proteomes of 19 archived second-trimester cord blood samples representing highest and lowest serum fluoride concentrations from a cohort of 48 women living in Northern California, previously analyzed for serum, urine and amniotic fluoride concentrations, were characterized by mass spectrometry. Proteins highly correlated to maternal serum fluoride concentrations were identified, and further compared in a group of samples from women with the highest serum fluoride to the group with the lowest maternal serum fluoride concentrations. Results Nine cord blood proteins were significantly correlated with maternal serum fluoride concentrations. Six of these proteins, including apolipoprotein B-100, delta homolog 1, coagulation factor X, mimecan, plasma kallikrein, and vasorin, were significantly decreased in the cord blood from women with the highest serum fluoride levels. Conclusion Changes in the relative amounts of second trimester cord blood proteins included proteins associated with the development of the fetal hematopoetic system.
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Affiliation(s)
| | - Dana E Goin
- University of California, San Francisco San Francisco
| | | | - Steven C Hall
- University of California, San Francisco San Francisco
| | - Aras N Mattis
- University of California, San Francisco San Francisco
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Grandjean P, Meddis A, Nielsen F, Beck IH, Bilenberg N, Goodman CV, Hu H, Till C, Budtz-Jørgensen E. Dose dependence of prenatal fluoride exposure associations with cognitive performance at school age in three prospective studies. Eur J Public Health 2024; 34:143-149. [PMID: 37798092 PMCID: PMC10843960 DOI: 10.1093/eurpub/ckad170] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/07/2023] Open
Abstract
BACKGROUND Fluoride may be a developmental neurotoxicant at elevated exposures. We merged new data from a prospective Odense Child Cohort (OCC) with results from two previous birth cohort studies from Mexico and Canada to characterize the dose-effect relationship in greater detail. METHODS The OCC contributed 837 mother-child pairs to the total of >1500. We measured creatinine-adjusted urine-fluoride concentrations in maternal urine samples obtained during late pregnancy. Child IQ was determined at age 7 years using an abbreviated version of the Wechsler Intelligence Scales for Children. Findings from the three cohorts were used to calculate the joint benchmark concentration (BMC) and the lower confidence limit (BMCL) after adjustment for covariables. RESULTS In the OCC, urine-fluoride concentrations varied between 0.08 and 3.04 mg/l (median 0.52 mg/l) but were not significantly associated with full-scale IQ at age 7 years (β = 0.08; 95% confidence interval -1.14 to 1.30 for a doubling in exposure). No difference was apparent between boys and girls. In the OCC, the BMC was 0.92 mg/l, with a BMCL of 0.30 mg/l. The joint analysis of all three cohorts showed a statistically significant association between urine-fluoride and IQ, with a BMC of 0.45 mg/l (BMCL, 0.28 mg/l), slightly higher than the BMC previously reported for the two North American cohorts alone. CONCLUSIONS As the BMCL reflects an approximate threshold for developmental neurotoxicity, the results suggest that pregnant women and children may need protection against fluoride toxicity.
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Affiliation(s)
- Philippe Grandjean
- Department of Environmental Medicine, University of Southern Denmark, Odense, Denmark
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | | | - Flemming Nielsen
- Department of Environmental Medicine, University of Southern Denmark, Odense, Denmark
| | - Iben H Beck
- Department of Environmental Medicine, University of Southern Denmark, Odense, Denmark
| | - Niels Bilenberg
- Department of Child and Adolescent Psychiatry, Odense University Hospital, Odense, Denmark
| | - Carly V Goodman
- Department of Psychology, Faculty of Health, York University, Toronto, ON, Canada
| | - Howard Hu
- Department of Population and Public Health Sciences, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Christine Till
- Department of Psychology, Faculty of Health, York University, Toronto, ON, Canada
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González-Martínez F, Gómez-Scarpetta R, Salcedo OB, Bermúdez-Reyes P, Castro-Villamizar P, Cerezo MDP, Martínez C, Tirado-Amador L, Salas-Zambrano A, Saldarriaga A, Sánchez-Molina M, Vila LA. Enamel fluorosis related with fluoride-containing water ingestion and urinary excretion in schoolchildren. J Clin Exp Dent 2024; 16:e51-e61. [PMID: 38314340 PMCID: PMC10837805 DOI: 10.4317/jced.61052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 10/23/2023] [Indexed: 02/06/2024] Open
Abstract
Background Natural water sources are considered as the major environmental exposure of fluoride, resulting in increased prevalence of enamel fluorosis. This type of natural exposure should be permanently monitored to avoid the interactions with other non-natural fluoride sources. We evaluated the prevalence of enamel fluorosis in Colombian schoolchildren and its relationship with fluoride-containing water ingestion exposure dose and urinary fluoride excretion. Material and Methods We included 923 schoolchildren aged 7-12 years residing in eight municipalities in Colombia. Sampling of consumption water was performed in major aquifers used for daily supply. Samples were collected in 98 polyethylene containers and refrigerated until analysis. Water and urine fluoride concentrations were measured using the fluoride selective electrode method. Enamel fluorosis was evaluated using Thylstrup and Ferjerskov Index (TFI). Demographic and anthropometric characteristics were assessed. Besides, other exposures to non-natural fluoride were also evaluated. Logistic regression was applied for multiple analyses. Results The median fluoride concentration in water and urine samples was 10.5 mg/L and 0.63 mg/L respectively, with the highest value found in Algarrobo-Magdalena, and the lowest value found in Manzanares-Caldas. The overall prevalence of enamel fluorosis was 86.1%, being more frequent the mild codes with TFI-1 to TFI-2. The highest prevalence was found in Margarita-Bolívar and Manzanares-Caldas, and the most severe codes (TFI-5 to TFI-9) were detected in Manzanares-Caldas. The multiple analysis revealed water ingestion exposure dose, urinary excretion, involuntary intake of toothpaste, amount of table salt consumption and sex as significant factors (p< 0.001). Conclusions The fluoride ingestion exposure dose and its subsequent urinary excretion could be used as estimators of past fluoride exposure, explaining the current prevalence of enamel fluorosis in Colombian schoolchildren. Key words:Fluoride, groundwater ingestion, enamel fluorosis, prevalence, severity.
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Affiliation(s)
- Farith González-Martínez
- DDS, MSPH, PhD. Public Health Research Group Universidad de Cartagena-Cartagena de Indias, Colombia
- Asociación Colombiana de Facultades de Odontología-Bogotá-ACFO, Colombia
- Latin American Network of Research on Fluorides and Dental Fluorosis, Cartagena 130014, Colombia
| | - Ruth Gómez-Scarpetta
- Latin American Network of Research on Fluorides and Dental Fluorosis, Cartagena 130014, Colombia
- BAM, MSc. Universidad Cooperativa de Colombia-Villavicencio, Colombia
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Taher MK, Momoli F, Go J, Hagiwara S, Ramoju S, Hu X, Jensen N, Terrell R, Hemmerich A, Krewski D. Systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water. Crit Rev Toxicol 2024; 54:2-34. [PMID: 38318766 DOI: 10.1080/10408444.2023.2295338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 11/27/2023] [Indexed: 02/07/2024]
Abstract
INTRODUCTION Fluoride is a naturally occurring substance that is also added to drinking water, dental hygiene products, and food supplements for preventing dental caries. Concerns have been raised about several other potential health risks of fluoride. OBJECTIVE To conduct a robust synthesis of evidence regarding human health risks due to exposure to fluoride in drinking water, and to develop a point of departure (POD) for setting a health-based value (HBV) for fluoride in drinking water. METHODS A systematic review of evidence published since recent reviews of human, animal, and in vitro data was carried out. Bradford Hill considerations were used to weigh the evidence for causality. Several key studies were considered for deriving PODs. RESULTS The current review identified 89 human studies, 199 animal studies, and 10 major in vitro reviews. The weight of evidence on 39 health endpoints was presented. In addition to dental fluorosis, evidence was considered strong for reduction in IQ scores in children, moderate for thyroid dysfunction, weak for kidney dysfunction, and limited for sex hormone disruptions. CONCLUSION The current review identified moderate dental fluorosis and reduction in IQ scores in children as the most relevant endpoints for establishing an HBV for fluoride in drinking water. PODs were derived for these two endpoints, although there is still some uncertainty in the causal weight of evidence for causality for reducing IQ scores in children and considerable uncertainty in the derivation of its POD. Given our evaluation of the overall weight of evidence, moderate dental fluorosis is suggested as the key endpoint until more evidence is accumulated on possible reduction of IQ scores effects. A POD of 1.56 mg fluoride/L for moderate dental fluorosis may be preferred as a starting point for setting an HBV for fluoride in drinking water to protect against moderate and severe dental fluorosis. Although outside the scope of the current review, precautionary concerns for potential neurodevelopmental cognitive effects may warrant special consideration in the derivation of the HBV for fluoride in drinking water.
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Affiliation(s)
- Mohamed Kadry Taher
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- School of Mathematics and Statistics, Carleton University, Ottawa, ON, Canada
| | - Franco Momoli
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Jennifer Go
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Shintaro Hagiwara
- School of Mathematics and Statistics, Carleton University, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Siva Ramoju
- Risk Sciences International, Ottawa, ON, Canada
| | - Xuefeng Hu
- Department of Biology, Faculty of Science, University of Ottawa, Ottawa, ON, Canada
| | - Natalie Jensen
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Rowan Terrell
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
| | - Alex Hemmerich
- Risk Sciences International, Ottawa, ON, Canada
- Faculty of Education, Queen's University, Kingston, ON, Canada
| | - Daniel Krewski
- McLaughlin Centre for Population Health Risk Assessment, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- School of Epidemiology and Public Health, University of Ottawa, Ottawa, ON, Canada
- School of Mathematics and Statistics, Carleton University, Ottawa, ON, Canada
- Risk Sciences International, Ottawa, ON, Canada
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12
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Zhu X, Zhang S, Liu X, Li H, Zhu X, Zhang J, Wang X, Zhang M. Integrative transcriptome and metabolome analysis of fluoride exposure induced developmental neurotoxicity in mouse brain. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 269:115752. [PMID: 38039848 DOI: 10.1016/j.ecoenv.2023.115752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 11/19/2023] [Accepted: 11/25/2023] [Indexed: 12/03/2023]
Abstract
Fluoride could cause developmental neurotoxicity and significantly affect the intelligence quotient (IQ) of children. However, the systematic mechanism of neuronal damage caused by excessive fluoride administration in offspring is largely unknown. Here, we present a comprehensive integrative transcriptome and metabolome analysis to study the mechanism of developmental neurotoxicity caused by chronic fluoride exposure. Comparing the different doses of fluoride treatments in two generations revealed the exclusive signature of metabolism pathways and gene expression profiles. In particular, neuronal development and synaptic ion transport are significantly altered at the gene expression and metabolite accumulation levels for both generations, which could act as messengers and enhancers of fluoride-induced systemic neuronal injury. Choline and arachidonic acid metabolism, which highlighted in the integrative analysis, exhibited different regulatory patterns between the two generations, particularly for synaptic vesicle formation and inflammatory factor transport. It may suggest that choline and arachidonic acid metabolism play important roles in developmental neurotoxic responses for offspring mice. Our study provides comprehensive insights into the metabolomic and transcriptomic regulation of fluoride stress responses in the mechanistic explanation of fluoride-induced developmental neurotoxicity.
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Affiliation(s)
- Xinliang Zhu
- College of Life Science, Northwest Normal University, Lanzhou 730070, Gansu Province, China; Bioactive Products Engineering Research Center for Gansu Distinctive Plants, Lanzhou 730070, China; Institute of Rural Development and Research, Northwest Normal University, Lanzhou 730070, Gansu Province, China.
| | - Shunbin Zhang
- College of Life Science, Northwest Normal University, Lanzhou 730070, Gansu Province, China
| | - Xiaoxiao Liu
- Lanzhou Institute of Food and Drug Control, Lanzhou 740050, China
| | - Huixia Li
- Gansu Tongxing Intelligent Technology Development Co., Ltd., Lanzhou 730070, Gansu Province, China
| | - Xinyu Zhu
- Department of General Surgery, Gansu Provincial Hospital, Lanzhou 730000, China
| | - Ji Zhang
- College of Life Science, Northwest Normal University, Lanzhou 730070, Gansu Province, China; Bioactive Products Engineering Research Center for Gansu Distinctive Plants, Lanzhou 730070, China; Institute of Rural Development and Research, Northwest Normal University, Lanzhou 730070, Gansu Province, China
| | - Xiaopeng Wang
- Department of General Surgery, Gansu Provincial Hospital, Lanzhou 730000, China
| | - Min Zhang
- Department of Scientific Research, Gansu Provincial Hospital, Lanzhou 730000, China; Department of General Surgery, Gansu Provincial Hospital, Lanzhou 730000, China.
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13
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Li Y, Zhang M, Mi W, Ji L, He Q, Xie S, Xiao C, Bi Y. Spatial distribution of groundwater fluoride and arsenic and its related disease in typical drinking endemic regions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167716. [PMID: 37820791 DOI: 10.1016/j.scitotenv.2023.167716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 08/22/2023] [Accepted: 10/08/2023] [Indexed: 10/13/2023]
Abstract
c exposure to geogenic fluoride and arsenic iChronic exposure to geogenic fluoride and arsenic in groundwater has a deleterious influence on the health of billions of people globally. The health status of residents impacted by connected diseases is urgently needed. A twelve-year study was carried out to identify the spatial distribution pattern of high fluoride/arsenic groundwater in an arid/semi-arid area and to estimate the population exposed to related disease. A geostatistical interpolation method and a disease inversion model were used. The results indicated that fluoride/arsenic-rich groundwater primarily accumulated in basins of Shanxi Province. Groundwater fluoride exposure provided a health concern to 3.16 million persons (9.08 % of the population), including 2.50 million children at risk of dental caries. Exposure to groundwater arsenic caused a health risk to 4.38 million inhabitants (12.58 % of total), with 1.92 million at risk of lung cancer, 1.87 million at risk of bladder cancer, and 0.29 million at risk of skin cancer, respectively. The pollution and impact of groundwater fluoride and arsenic vary greatly among residents in different environments, and accurate assessment of the affected population is of great significance for residents' health and water quality management. Our research study complements the critical data on the disease risks associated with geogenic-contaminated groundwater and provides scientific basis of water quality management for policy makers.
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Affiliation(s)
- Yuan Li
- School of Environment and Resources, Taiyuan University of Science and Technology, Taiyuan 030024, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Minghua Zhang
- School of Environment and Resources, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Wujuan Mi
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Li Ji
- School of Environment and Resources, Taiyuan University of Science and Technology, Taiyuan 030024, China
| | - Qiusheng He
- Institute of Intelligent Low Carbon and Control Technology, Taiyuan University of Science and Technology, Taiyuan 030024, China; Shanxi Polytechnic College, Taiyuan 030006, China
| | - Shulian Xie
- School of Life Science, Shanxi University, Taiyuan 030006, China
| | - Chen Xiao
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Yonghong Bi
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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14
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Velez-León E, Pacheco-Quito EM, Díaz-Dosque M, Tobar-Almache D. Worldwide Variations in Fluoride Content in Beverages for Infants. CHILDREN (BASEL, SWITZERLAND) 2023; 10:1896. [PMID: 38136098 PMCID: PMC10741400 DOI: 10.3390/children10121896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 11/22/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023]
Abstract
In situations where breastfeeding is impractical, milk formulas have emerged as the primary choice for infant nutrition. Numerous global studies have scrutinized the fluoride content in these formulas, uncovering fluctuations in fluoride levels directly associated with the method of preparation. This variability poses a potential risk of elevated fluoride concentrations and, consequently, an increased susceptibility to dental fluorosis in infants. The primary objective of this review is to intricately delineate the fluoride content in dairy formulas and emphasize the variability of these values concerning their reconstitution process. The review's findings reveal that, among the 17 studies assessing fluoride levels in infant formula, milk-based formulas exhibit a range of 0.01-0.92 ppm, with only two studies exceeding 1.30 ppm. Conversely, soy-based formulas demonstrate values ranging from 0.13-1.11 ppm. In conclusion, the observed variability in fluoride levels in infant formulas is ascribed to the choice of the water source employed in the preparation process. This underscores the paramount importance of meticulously adhering to recommendations and guidelines provided by healthcare professionals concerning the utilization of these formulas and their meticulous reconstitution.
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Affiliation(s)
- Eleonor Velez-León
- Unidad Académica de Salud y Bienestar, Facultad de Odontología, Universidad Católica de Cuenca, Cuenca 010105, Ecuador;
- Grupo de Investigación Innovación y Desarrollo Farmacéutico en Odontología, Facultad de Odontología, Jefatura de Investigación e Innovación, Universidad Católica de Cuenca, Cuenca 010105, Ecuador
- Latin American Network of Research on Fluorides and Dental Fluorosis, Cartagena 130009, Colombia; (M.D.-D.); (D.T.-A.)
| | - Edisson-Mauricio Pacheco-Quito
- Unidad Académica de Salud y Bienestar, Facultad de Odontología, Universidad Católica de Cuenca, Cuenca 010105, Ecuador;
- Grupo de Investigación Innovación y Desarrollo Farmacéutico en Odontología, Facultad de Odontología, Jefatura de Investigación e Innovación, Universidad Católica de Cuenca, Cuenca 010105, Ecuador
- Latin American Network of Research on Fluorides and Dental Fluorosis, Cartagena 130009, Colombia; (M.D.-D.); (D.T.-A.)
| | - Mario Díaz-Dosque
- Latin American Network of Research on Fluorides and Dental Fluorosis, Cartagena 130009, Colombia; (M.D.-D.); (D.T.-A.)
- Laboratory of Pharmacology, Institute for Research in Dental Sciences (ICOD), Faculty of Dentistry, University of Chile, Olivos 943, Independencia, Santiago 8380544, Chile
| | - Daniela Tobar-Almache
- Latin American Network of Research on Fluorides and Dental Fluorosis, Cartagena 130009, Colombia; (M.D.-D.); (D.T.-A.)
- Laboratory of Pharmacology, Institute for Research in Dental Sciences (ICOD), Faculty of Dentistry, University of Chile, Olivos 943, Independencia, Santiago 8380544, Chile
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15
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Fisher M, Muckle G, Lanphear B, Arbuckle TE, Braun JM, Zidek A, Vélez MP, Lupien N, Bastien S, Ashley-Martin J, Oulhote Y, Borghese MM, Walker M, Asztalos E, Bouchard MF, Booij L, Palmert MR, Morrison KM, Cummings EA, Khatchadourian K, Panagiotopoulos C, Glendon G, Shutt R, Abdul-Fatah A, Seal K, Fraser WD. Cohort profile update: The Canadian Maternal-Infant Research on Environmental Chemicals Child Development study (MIREC-CD PLUS). Paediatr Perinat Epidemiol 2023; 37:719-732. [PMID: 37921434 DOI: 10.1111/ppe.13013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 09/11/2023] [Accepted: 10/01/2023] [Indexed: 11/04/2023]
Abstract
BACKGROUND The pan-Canadian Maternal-Infant Research on Environmental Chemicals (MIREC) study was established to determine whether maternal environmental chemical exposures were associated with adverse pregnancy outcomes in 2001 pregnant women. OBJECTIVES The MIREC-Child Development (CD PLUS) study followed this cohort with the goal of assessing the potential effects of prenatal exposures on anthropometry and neurodevelopment in early childhood. POPULATION MIREC families with children between the ages of 15 months and 5 years who had agreed to be contacted for future research (n = 1459) were invited to participate in MIREC-CD PLUS which combines data collected from an online Maternal Self-Administered Questionnaire with biomonitoring and neurodevelopment data collected from two in-person visits. PRELIMINARY RESULTS Between April 2013 and March 2015, 803 children participated in the Biomonitoring visit where we collected anthropometric measures, blood, and urine from the children. The Behavioural Assessment System for Children-2, Behaviour Rating Inventory of Executive Function, MacArthur-Bates Communicative Development Inventories and the Communication subscale of the Adaptive Behaviour Scale from the Bayley Scales of Infant and Toddler Development-III are available on close to 900 children. There were 610 singleton children who completed in-person visits for neurodevelopment assessments including the Social Responsiveness Scale, Wechsler Preschool Primary Scale of Intelligence-III and NEuroPSYchological assessments (NEPSY). Currently, we are following the cohort into early adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO). CONCLUSIONS Data collection for the MIREC-CD PLUS study is complete and analysis of the data continues. We are now extending the follow-up of the cohort into adolescence to measure the impact of early life exposures on endocrine and metabolic function (MIREC-ENDO). MIREC-CD PLUS is limited by loss to follow-up and the fact that mothers are predominately of higher socioeconomic status and 'White' ethnicity, which limits our generalizability. However, the depth of biomonitoring and clinical measures in MIREC provides a platform to examine associations of prenatal, infancy and childhood exposures with child growth and development.
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Affiliation(s)
- Mandy Fisher
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | | | - Bruce Lanphear
- Simon Fraser University, Vancouver, British Columbia, Canada
| | - Tye E Arbuckle
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Joseph M Braun
- Department of Epidemiology, Brown University, Providence, Rhode Island, USA
| | - Angelika Zidek
- Existing Substances and Risk Assessment Bureau, Health Canada, Ottawa, Ontario, Canada
| | | | - Nicole Lupien
- Sainte-Justine University Hospital Research Center, Montreal, Quebec, Canada
| | - Stephanie Bastien
- Sainte-Justine University Hospital Research Center, Montreal, Quebec, Canada
| | - Jillian Ashley-Martin
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Youssef Oulhote
- Department of Epidemiology and Biostatistics, School of Public Health and Health Sciences, University of Massachusetts, Boston, Massachusetts, USA
| | - Michael M Borghese
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Mark Walker
- The Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Elizabeth Asztalos
- Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Maryse F Bouchard
- Sainte-Justine University Hospital Research Center, Montreal, Quebec, Canada
- Institut National de la Recherche Scientifique, Montreal, Quebec, Canada
| | - Linda Booij
- Sainte-Justine University Hospital Research Center, Montreal, Quebec, Canada
- Department of Psychiatry, McGill University, Montreal, Quebec, Canada
- Research Centre/Eating Disorders Continuum, Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Mark R Palmert
- Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Katherine M Morrison
- Department of Pediatrics, Centre for Metabolism, Obesity and Diabetes Research, McMaster University, Hamilton, Ontario, Canada
| | | | | | - Constadina Panagiotopoulos
- Endocrinology and Diabetes Unit, Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Gord Glendon
- Ontario Cancer Genetics Network, Lunenfeld-Tanenbaum Research Institute, Toronto, Ontario, Canada
| | - Robin Shutt
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Ammanie Abdul-Fatah
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - Kelsey Seal
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, Ontario, Canada
| | - William D Fraser
- Department of Obstetrics and Gynecology, Centre de Recherche du CHUS, University of Sherbrooke, Sherbrooke, Québec, Canada
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16
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Nelima D, Wambu EW, Kituyi JL. Fluoride distribution in selected foodstuffs from Nakuru County, Kenya, and the risk factors for its human overexposure. Sci Rep 2023; 13:15295. [PMID: 37714918 PMCID: PMC10504336 DOI: 10.1038/s41598-023-41601-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 08/29/2023] [Indexed: 09/17/2023] Open
Abstract
Critical data on the impacts of fluoride (F) in food systems along the Eastern Africa Rift Valley System (EARS) is needed for public health risk assessment and for the development of strategies for ameliorating its deleterious effects among the affected communities. Long-term F overexposure causes dental and skeletal fluorosis, and leads to neurotoxicity, which impacts several important body functions. Investigating F exposure pathways is of essence to inform and safeguard public health of the affected communities. The current study assessed the F levels in potatoes (Solanum tuberosum L.), beans (Phaseolus vulgaris L.) and garden peas (Possum sativa) from Nakuru County, Kenya, by potentiometric analysis using F ion-selective electrodes. It then evaluated the risk factors for excessive human exposure to F through contaminated foodstuffs. The mean F levels in the potatoes (8.50 ± 4.70 mg/kg), beans (8.02 ± 4.12 mg/kg) and peas (4.99 ± 1.25 mg/kg) exceeded recommended dietary allowances (RDA) level of 4 mg/kg endorsed by US Institute of Medicine for the different categories of people. The F distribution trends in beans and potatoes reflected the environmental patterns of F contamination of the study area but the spatial extent Fin the peas indicated existence of partial resistance of the pea plants to environmental F uptake. The results indicated that both the beans and the potatoes were more liable to accumulating greater amounts of F from the environment than garden peas and that all the three foodstuffs contained high F levels that posed greater risk of F overexposure and its deleterious impacts among the young children, male populations, and in people of greater body weight and high physical activity levels.
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Affiliation(s)
- Delphine Nelima
- Department of Chemistry, School of Science, University of Eldoret, P.O. BOX, Eldoret, 1125-30100, Kenya
| | - Enos W Wambu
- Department of Chemistry, School of Science, University of Eldoret, P.O. BOX, Eldoret, 1125-30100, Kenya.
| | - John L Kituyi
- Department of Chemistry, School of Science, University of Eldoret, P.O. BOX, Eldoret, 1125-30100, Kenya
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17
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Afarinandeh A, Heidari K, Barczak M, Abdellattif MH, Izadi Yazdanaabadi Z, Mohammadi AA, Haghighat GA, Shams M. Controlled removal of fluoride by ZIF-8, ZIF-67, and Ni-MOF of different morphologies. ARAB J CHEM 2023. [DOI: 10.1016/j.arabjc.2023.104837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
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18
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Rocha-Amador DO, González-Martell AD, Pérez-Vázquez FJ, Cilia López VG. Health Risk Assessment in Mexican Children Exposed to Fluoride from Sweetened Beverages. Biol Trace Elem Res 2023; 201:2250-2257. [PMID: 35854170 DOI: 10.1007/s12011-022-03350-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 07/01/2022] [Indexed: 12/07/2022]
Abstract
The primary source of fluoride exposure is groundwater, but evidence suggests that beverages and food are additional fluoride sources. Intake of these products at an early age affects the optimal functioning of soft organs. An increase in sweetened beverage consumption by the pediatric population has been reported, suggesting an increase in fluoride exposure. The objectives of this study were to determine the fluoride concentrations in beverages and analyze the risk to human health from fluoride exposure to sweetened beverages consumed by children. Eighty-two sugar-sweetened beverages produced in different Mexican states were analyzed. The fluoride determination was carried out with an ion-selective electrode. The highest fluoride concentration was 1.92 mg/L; 73.2% of beverages showed fluoride values above permitted limits. Low-cost beverages had the highest fluoride values, suggesting that the water used for their production does not comply with fluorine regulations. According to the risk assessment in children from 3 to 6 years, the daily consumption of juices and sodas with concentrations that exceeded the normative of 0.7 mg/L could represent a risk to dental fluorosis development. It is crucial to control fluoride and regulate its concentrations in beverages for children to ensure food safety, especially in areas of endemic hydrofluorosis.
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Affiliation(s)
- Diana Olivia Rocha-Amador
- Departamento de Farmacia, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato, Mexico
- Facultad de Medicina-CIACYT, Universidad Autónoma de San Luis Potosí, San Luis Potosi, Mexico
| | - Andrea Daniela González-Martell
- Programa Multidisciplinario de Posgrado en Ciencias Ambientales (PMPCA), Universidad Autónoma de San Luis Potosí, San Luis Potosi, Mexico
- Facultad de Medicina-CIACYT, Universidad Autónoma de San Luis Potosí, San Luis Potosi, Mexico
| | - Francisco Javier Pérez-Vázquez
- CONACYT Research Fellow, Coordinación para la Innovación y Aplicación de la Ciencia y la Tecnología (CIACYT), Universidad Autónoma de San Luis Potosí, San Luis Potosi, Mexico
| | - Virginia Gabriela Cilia López
- CONACYT Research Fellow, Coordinación para la Innovación y Aplicación de la Ciencia y la Tecnología (CIACYT), Universidad Autónoma de San Luis Potosí, San Luis Potosi, Mexico.
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19
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Fiore G, Veneri F, Di Lorenzo R, Generali L, Vinceti M, Filippini T. Fluoride Exposure and ADHD: A Systematic Review of Epidemiological Studies. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:medicina59040797. [PMID: 37109754 PMCID: PMC10143272 DOI: 10.3390/medicina59040797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/12/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023]
Abstract
Background and objectives: Attention deficit hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder characterized by two dimensions: inattentiveness and hyperactivity/impulsivity. ADHD may be the result of complex interactions between genetic, biological and environmental factors possibly including fluoride exposure. Materials and methods: A literature search was performed on 31 March 2023 in the following databases: PubMed, Embase and Web of Science. We defined the following inclusion criteria according to the PECOS statement: a healthy child and adolescent population (P), fluoride exposure of any type (E), comparison with low or null exposure (C), ADHD spectrum disorder (O), and ecological, cross-sectional, case-control and cohort studies (S). Results: We found eight eligible records corresponding to seven different studies investigating the effect of fluoride exposure on children and adolescents. One study had a cohort design and one a case-control one, while five were cross-sectional. Only three studies applied validated questionnaires for the purpose of ADHD diagnosis. As regards exposure assessment, levels of fluoride in urine and tap water were, respectively used in three and two studies, while two used both. Three studies reported a positive association with ADHD risk, all assessing exposure through fluoride levels. By using urinary fluoride, conversely, a positive correlation with inattention, internalizing symptoms, cognitive and psychosomatic problems was found in three studies, but no relation was found in the other one. Conclusions: The present review suggests that early exposure to fluoride may have neurotoxic effects on neurodevelopment affecting behavioral, cognitive and psychosomatic symptoms related to ADHD diagnosis. However, due to the heterogeneity of the studies included, current evidence does not allow to conclusively confirm that fluoride exposure is specifically linked to ADHD development.
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Affiliation(s)
- Gianluca Fiore
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Federica Veneri
- Unit of Dentistry & Oral-Maxillo-Facial Surgery, Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), University of Modena and Reggio Emilia, 41124 Modena, Italy
- PhD Program in Clinical and Experimental Medicine, Department of Biomedical, Metabolic and Neural Sciences-University of Modena and Reggio Emilia, 41125 Modena, Italy
| | - Rosaria Di Lorenzo
- Service of Psychiatric Diagnosis and Care (SPDC), Department of Mental Health and Drug Abuse, AUSL Modena, 41124 Modena, Italy
| | - Luigi Generali
- Unit of Dentistry & Oral-Maxillo-Facial Surgery, Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), University of Modena and Reggio Emilia, 41124 Modena, Italy
| | - Marco Vinceti
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
- Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA
| | - Tommaso Filippini
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Section of Public Health, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy
- School of Public Health, University of California Berkeley, Berkeley, CA 94704, USA
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20
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Veneri F, Vinceti M, Generali L, Giannone ME, Mazzoleni E, Birnbaum LS, Consolo U, Filippini T. Fluoride exposure and cognitive neurodevelopment: Systematic review and dose-response meta-analysis. ENVIRONMENTAL RESEARCH 2023; 221:115239. [PMID: 36639015 DOI: 10.1016/j.envres.2023.115239] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Many uncertainties still surround the possible harmful effect of fluoride exposure on cognitive neurodevelopment in children. The aim of this systematic review and meta-analysis was to characterize this relation through a dose-response approach, by comparing the intelligence quotient (IQ) scores in the highest versus the lowest fluoride exposure category with a random-effects model, within a one-stage dose-response meta-analysis based on a cubic spline random-effects model. Out of 1996 potentially relevant literature records, 33 studies were eligible for this review, 30 of which were also suitable for meta-analysis. The summary mean difference of IQ score, comparing highest versus lowest fluoride categories and considering all types of exposure, was -4.68 (95% confidence interval-CI -6.45; -2.92), with a value of -5.60 (95% CI -7.76; -3.44) for drinking water fluoride and -3.84 (95% CI -7.93; 0.24) for urinary fluoride. Dose-response analysis showed a substantially linear IQ decrease for increasing water fluoride above 1 mg/L, with -3.05 (95% CI -4.06; -2.04) IQ points per 1 mg/L up to 2 mg/L, becoming steeper above such level. A weaker and substantially linear decrease of -2.15 (95% CI -4.48; 0.18) IQ points with increasing urinary fluoride emerged above 0.28 mg/L (approximately reflecting a water fluoride content of 0.7 mg/L). The inverse association between fluoride exposure and IQ was particularly strong in the studies at high risk of bias, while no adverse effect emerged in the only study judged at low risk of bias. Overall, most studies suggested an adverse effect of fluoride exposure on children's IQ, starting at low levels of exposure. However, a major role of residual confounding could not be ruled out, thus indicating the need of additional prospective studies at low risk of bias to conclusively assess the relation between fluoride exposure and cognitive neurodevelopment.
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Affiliation(s)
- Federica Veneri
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), Unit of Dentistry & Oral-Maxillo-Facial Surgery - University of Modena and Reggio Emilia, Modena, Italy; PhD Program in Clinical and Experimental Medicine, Department of Biomedical, Metabolic and Neural Sciences - University of Modena and Reggio Emilia, Modena, Italy
| | - Marco Vinceti
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, Medical School - University of Modena and Reggio Emilia, Modena, Italy; Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA.
| | - Luigi Generali
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), Unit of Dentistry & Oral-Maxillo-Facial Surgery - University of Modena and Reggio Emilia, Modena, Italy
| | - Maria Edvige Giannone
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, Medical School - University of Modena and Reggio Emilia, Modena, Italy
| | - Elena Mazzoleni
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, Medical School - University of Modena and Reggio Emilia, Modena, Italy
| | - Linda S Birnbaum
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Ugo Consolo
- Department of Surgery, Medicine, Dentistry and Morphological Sciences with Transplant Surgery, Oncology and Regenerative Medicine Relevance (CHIMOMO), Unit of Dentistry & Oral-Maxillo-Facial Surgery - University of Modena and Reggio Emilia, Modena, Italy
| | - Tommaso Filippini
- Environmental, Genetic and Nutritional Epidemiology Research Center (CREAGEN), Department of Biomedical, Metabolic and Neural Sciences, Medical School - University of Modena and Reggio Emilia, Modena, Italy; School of Public Health, University of California Berkeley, Berkeley, CA, USA
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21
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A Scoping Review of Iodine and Fluoride in Pregnancy in Relation to Maternal Thyroid Function and Offspring Neurodevelopment. Adv Nutr 2023; 14:317-338. [PMID: 36796438 DOI: 10.1016/j.advnut.2023.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/05/2023] [Accepted: 01/11/2023] [Indexed: 02/04/2023] Open
Abstract
Iodine (I), an essential nutrient, is important for thyroid function and therefore growth and development. Fluoride (F), also an essential nutrient, strengthens bones and teeth, and prevents childhood dental caries. Both severe and mild-to-moderate I deficiency and high F exposure during development are associated to decreased intelligence quotient with recent reports associating high levels of F exposure during pregnancy and infancy to low intelligence quotient. Both F and I are halogens, and it has been suggested that F may interfere with the role of I in thyroid function. We provide a scoping review of the literature on I and F exposure dur pregnancy and their individual effects on thyroid function and offspring neurodevelopment. We first discuss I intake and status in pregnancy and the relationship to thyroid function and offspring neurodevelopment. We follow with the F in pregnancy and offspring neurodevelopment. We then review the interaction between I and F on thyroid function. We searched for, and found only one study that assessed both I and F in pregnancy. We conclude more studies are needed.
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22
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Revelo-Mejía IA, Alejandro-Vega S, Paz-Montelongo S, Niebla-Canelo D, Cerdán-Pérez S, Rubio-Armendáriz C, Gutiérrez-Fernández ÁJ, Hardisson A, Rodríguez-Díaz R, Hernández-Sánchez C. Fluoride Levels in Supply Water from the Canary Islands Region. Foods 2023; 12:foods12040745. [PMID: 36832820 PMCID: PMC9956124 DOI: 10.3390/foods12040745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/20/2023] [Accepted: 02/06/2023] [Indexed: 02/10/2023] Open
Abstract
The Canary Islands, located in the Atlantic Ocean, are an archipelago of volcanic origin which, for decades, has been affected by natural fluoride contamination in the water supply of some of its islands, mainly the island of Tenerife. In addition, recent volcanic eruptions in the archipelago and the increased demand for water supply have led to an increase in the fluoride content in other areas which, historically, were not affected. Fluoride content was determined in 274 water supply samples from the most populated islands of the Canary Islands (Tenerife and Gran Canaria) collected during the months of June 2021 to May 2022. The samples were analysed by fluoride ion selective potentiometry. The highest concentrations in Tenerife were found in the municipalities of Sauzal (7.00 mg/L) and Tegueste (5.39 mg/L), both water samples are over the parametric value of 1.5 mg/L set in the supply water legislation. In the Gran Canaria Island, the highest fluoride levels were found in Valsequillo and Mogán with 1.44 mg/L in both locations, but under the parametric fluoride value abovementioned. Consumption of just 1 L of water per day in the El Sauzal area would result in a contribution rate of 77% for adults and children over 15 years of age (Upper Level value of 7 mg/day) and 108% for children 9-14 years of age (UL value of 5 mg/day). The contribution rates increase considerably, reaching or exceeding 100% of the reference value (UL) with increasing consumption of 1 to 2 L of water per day. Therefore, it is considered that there is a health risk of overexposure to fluoride on the island of Tenerife. In the case of the island of Gran Canaria, it has been shown that even the consumption of 2 litres of water per day does not confer contribution rates that pose a health risk.
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Affiliation(s)
- Inés A. Revelo-Mejía
- Faculty of Odontology, Universidad Antonio Nariño, 37-94 Calle 58 A Bis, Bogota 111321, Cauca, Colombia
| | - Samuel Alejandro-Vega
- Area of Toxicology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
| | - Soraya Paz-Montelongo
- Area of Toxicology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Correspondence: ; Tel.: +34-634541612
| | - Daniel Niebla-Canelo
- Area of Toxicology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
| | - Santiago Cerdán-Pérez
- Area of Toxicology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
| | - Carmen Rubio-Armendáriz
- Area of Toxicology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
| | - Ángel J. Gutiérrez-Fernández
- Area of Toxicology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
| | - Arturo Hardisson
- Area of Toxicology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
| | - Rubí Rodríguez-Díaz
- Human Reproduction Unit, Hospital Universitario de Canarias, Carretera Ofra S/N, 38320 La Laguna, Tenerife, Canary Islands, Spain
- Area of Obstetrics and Gynecology, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
| | - Cintia Hernández-Sánchez
- Grupo Interuniversitario de Toxicología Alimentaria y Ambiental, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
- Area of Preventive Medicine and Public Health, Universidad de La Laguna, 38071 La Laguna, Tenerife, Canary Islands, Spain
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23
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Relationships between maternal body mass index and child cognitive outcomes at 3 years of age are buffered by specific early environments in a prospective Canadian birth cohort. J Dev Orig Health Dis 2023; 14:42-52. [PMID: 35481433 DOI: 10.1017/s2040174422000228] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Fetal and child development are shaped by early life exposures, including maternal health states, nutrition and educational and home environments. We aimed to determine if suboptimal pre-pregnancy maternal body mass index (BMI; underweight, overweight, obese) would associate with poorer cognitive outcomes in children, and whether early life nutritional, educational and home environments modify these relationships. Self-reported data were obtained from mother-infant dyads from the pan-Canadian prospective Maternal-Infant Research on Environmental Chemicals cohort. Relationships between potential risk factors (pre-pregnancy maternal BMI, breastfeeding practices and Home Observation Measurement of the Environment [HOME] score) and child cognitive development at age three (Weschler's Preschool and Primary Scale of Intelligence, Third Edition scale and its subcategories) were each evaluated using analysis of variance, multivariable regression models and moderating analyses. Amongst the 528 mother-child dyads, increasing maternal pre-pregnancy BMI was negatively associated with scores for child full-scale IQ (β [95% CI]; -2.01 [-3.43, -0.59], p = 0.006), verbal composite (-1.93 [-3.33, -0.53], p = 0.007), and information scale (-0.41 [-0.70, -0.14], p = 0.003) scores. Higher maternal education level or HOME score attenuated the negative association between maternal pre-pregnancy BMI and child cognitive outcome by 30%-41% and 7%-22%, respectively, and accounted for approximately 5%-10% greater variation in male children's cognitive scores compared to females. Maternal education and higher quality home environment buffer the negative effect of elevated maternal pre-pregnancy BMI on child cognitive outcomes. Findings suggest that relationships between maternal, social and environmental factors must be considered to reveal pathways that shape risk for, and resiliency against, suboptimal cognitive outcomes in early life.
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24
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Lubojanski A, Piesiak-Panczyszyn D, Zakrzewski W, Dobrzynski W, Szymonowicz M, Rybak Z, Mielan B, Wiglusz RJ, Watras A, Dobrzynski M. The Safety of Fluoride Compounds and Their Effect on the Human Body-A Narrative Review. MATERIALS (BASEL, SWITZERLAND) 2023; 16:1242. [PMID: 36770248 PMCID: PMC9920376 DOI: 10.3390/ma16031242] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/12/2023] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Fluoride is one of the elements commonly present in the human environment. Due to its characteristics, it is very widely used in medicine, dentistry, industry or agriculture. On the other hand, its universality possesses a real threat to the human body in the form of acute and chronic poisoning. The aim of this paper is to characterize the properties of fluoride and its effects on the human body, as well as the sources of its occurrence. Particular emphasis is placed on the safety of its use and optimal dosage intake, which prevents accumulation and reduces its potential side effects. The positive effect of proper fluoride supply is widely described. In order to avoid overdose, it is best to consult a specialist to properly select the dosage.
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Affiliation(s)
- Adam Lubojanski
- Department of Pediatric Dentistry and Preclinical Dentistry, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
| | - Dagmara Piesiak-Panczyszyn
- Department of Conservative Dentistry with Endodontics, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
| | - Wojciech Zakrzewski
- Pre-Clinical Research Centre, Wroclaw Medical University, Bujwida 44, 50-345 Wroclaw, Poland
| | - Wojciech Dobrzynski
- Department of Dentofacial Orthopedics and Orthodontics, Division of Facial Abnormalities, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
| | - Maria Szymonowicz
- Pre-Clinical Research Centre, Wroclaw Medical University, Bujwida 44, 50-345 Wroclaw, Poland
| | - Zbigniew Rybak
- Pre-Clinical Research Centre, Wroclaw Medical University, Bujwida 44, 50-345 Wroclaw, Poland
| | - Bartosz Mielan
- Pre-Clinical Research Centre, Wroclaw Medical University, Bujwida 44, 50-345 Wroclaw, Poland
| | - Rafal J. Wiglusz
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw, Poland
| | - Adam Watras
- Department of Pediatric Dentistry and Preclinical Dentistry, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw, Poland
| | - Maciej Dobrzynski
- Department of Pediatric Dentistry and Preclinical Dentistry, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okolna 2, 50-422 Wroclaw, Poland
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25
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Do LG, Spencer AJ, Sawyer A, Jones A, Leary S, Roberts R, Ha DH. Early Childhood Exposures to Fluorides and Child Behavioral Development and Executive Function: A Population-Based Longitudinal Study. J Dent Res 2023; 102:28-36. [PMID: 36214232 DOI: 10.1177/00220345221119431] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
It is important to both protect the healthy development and maintain the oral health of the child population. The study examined the effect of early childhood exposures to water fluoridation on measures of school-age executive functioning and emotional and behavioral development in a population-based sample. This longitudinal follow-up study used information from Australia's National Child Oral Health Study 2012-14. Children aged 5 to 10 y at baseline were contacted again after 7 to 8 y, before they had turned 18 y of age. Percent lifetime exposed to fluoridated water (%LEFW) from birth to the age 5 y was estimated from residential history and postcode-level fluoride levels in public tap water. Measures of children's emotional and behavioral development were assessed by the Strength and Difficulties Questionnaire (SDQ), and executive functioning was measured by the Behavior Rating Inventory of Executive Function (BRIEF). Multivariable regression models were generated to compare the associations between the exposure and the primary outcomes and controlled for covariates. An equivalence test was also conducted to compare the primary outcomes of those who had 100% LEFW against those with 0% LEFW. Sensitivity analysis was also conducted. A total of 2,682 children completed the SDQ and BRIEF, with mean scores of 7.0 (95% confidence interval, 6.6-7.4) and 45.3 (44.7-45.8), respectively. Those with lower %LEFW tended to have poorer scores of the SDQ and BRIEF. Multivariable regression models reported no association between exposure to fluoridated water and the SDQ and BRIEF scores. Low household income, identifying as Indigenous, and having a neurodevelopmental diagnosis were associated with poorer SDQ/BRIEF scores. An equivalence test confirmed that the SDQ/BRIEF scores among those with 100% LEFW were equivalent to that of those who had 0% LEFW. Exposure to fluoridated water during the first 5 y of life was not associated with altered measures of child emotional and behavioral development and executive functioning.
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Affiliation(s)
- L G Do
- School of Dentistry, Faculty of Health and Behavioural Sciences, The University of Queensland, Herston, Queensland, Australia
| | - A J Spencer
- Australian Research Centre for Population Oral Health, Adelaide Dental School, The University of Adelaide, Adelaide, Australia
| | - A Sawyer
- School of Psychology, The University of Adelaide, Adelaide, Australia
| | - A Jones
- School of Population and Global Health, Population and Public Health, The University of Western Australia, WA, Australia
| | - S Leary
- Bristol Dental School, University of Bristol, Bristol, UK
| | - R Roberts
- School of Psychology, The University of Adelaide, Adelaide, Australia
| | - D H Ha
- School of Dentistry, Faculty of Health and Behavioural Sciences, The University of Queensland, Herston, Queensland, Australia
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26
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Using Latent Profile Analysis to Identify Associations Between Gestational Chemical Mixtures and Child Neurodevelopment. Epidemiology 2023; 34:45-55. [PMID: 36166205 DOI: 10.1097/ede.0000000000001554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Unsupervised machine learning techniques have become increasingly popular for studying associations between gestational exposure mixtures and human health. Latent profile analysis is one method that has not been fully explored. METHODS We estimated associations between gestational chemical mixtures and child neurodevelopment using latent profile analysis. Using data from the Maternal-Infant Research on Environmental Chemicals (MIREC) research platform, a longitudinal cohort of pregnant Canadian women and their children, we generated latent profiles from 27 gestational exposure biomarkers. We then examined the associations between these profiles and child Verbal IQ, Performance IQ, and Full-Scale IQ, measured with the Wechsler Preschool and Primary Scale of Intelligence, Third Edition (WPPSI-III). We validated our findings using k-means clustering. RESULTS Latent profile analysis detected five latent profiles of exposure: a reference profile containing 61% of the study participants, a high monoethyl phthalate (MEP) profile with moderately low persistent organic pollutants (POPs) containing 26%, a high POP profile containing 6%, a low POP profile containing 4%, and a smoking chemicals profile containing 3%. We observed negative associations between both the smoking chemicals and high MEP profiles and all IQ scores and between the high POP profile and Full-Scale and Verbal IQ scores. We also found a positive association between the low POP profile and Full-Scale and Performance IQ scores. All associations had wide 95% confidence intervals. CONCLUSIONS Latent profile analysis is a promising technique for identifying patterns of chemical exposure and is worthy of further study for its use in examining complicated exposure mixtures.
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27
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Gopu BP, Azevedo LB, Duckworth RM, Subramanian MKP, John S, Zohoori FV. The Relationship between Fluoride Exposure and Cognitive Outcomes from Gestation to Adulthood-A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 20:22. [PMID: 36612346 PMCID: PMC9819484 DOI: 10.3390/ijerph20010022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/08/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Chronic exposure to high levels of fluoride may cause health concerns, including in cognitive function. This study reviewed the evidence on the association between fluoride exposure and cognitive outcomes in children from gestation up to 18 years old. A literature search was conducted for studies on pregnant women and children below 18, exposed to any source of fluoride, and assessed with a validated cognitive tool. The data were analyzed using a systematic narrative synthesis approach and by subgroup: study design, age of participants, levels of fluoride exposure and methodological quality. Our search retrieved 15,072 articles, of which 46 met the inclusion criteria. Only 6 of the studies had a longitudinal design; the remainder were cross-sectional. The levels of fluoride exposure were ≥2 mg/L in 27 studies and <2 mg/L in 13 studies; 6 studies did not report levels of fluoride exposure. Only 1 of 5 studies graded as excellent quality showed a negative association between fluoride exposure and cognitive outcomes, whereas 30 of 34 poor and fair quality studies reported a negative association. The overall evidence from this review suggests that high fluoride exposure might be associated with negative cognitive outcomes in children. However, more longitudinal studies with high methodological quality are needed on this topic.
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Affiliation(s)
- Banu Preethi Gopu
- School of Health &and Life Sciences, Teesside University, Middlesbrough TS1 3BX, UK
| | - Liane B. Azevedo
- School of Human and Health Sciences, University of Huddersfield, Huddersfield HD1 3DH, UK
| | - Ralph M. Duckworth
- School of Health &and Life Sciences, Teesside University, Middlesbrough TS1 3BX, UK
| | | | - Sherley John
- School of Health &and Life Sciences, Teesside University, Middlesbrough TS1 3BX, UK
| | - Fatemeh Vida Zohoori
- School of Health &and Life Sciences, Teesside University, Middlesbrough TS1 3BX, UK
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28
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Zhao Q, Pan W, Li J, Yu S, Liu Y, Zhang X, Qu R, Zhang Q, Li B, Yan X, Ren X, Qiu Y. Effects of neuron autophagy induced by arsenic and fluoride on spatial learning and memory in offspring rats. CHEMOSPHERE 2022; 308:136341. [PMID: 36087721 DOI: 10.1016/j.chemosphere.2022.136341] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 08/25/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
There are numerous studies showing that exposure to arsenic (As) or fluoride (F) damages the nervous system, but there is no literature investigating the effects of combined As and F exposure to induce autophagy on neurotoxicity in the offspring. In this study, we developed a rat model of As and/or F exposure through drinking water from before pregnancy to 90 days postnatal. The offspring rats were randomly divided into nine groups. Sodium arsenite (NaAsO2) (0, 35, 70 mg/L) and Sodium fluoride (NaF) (0, 50, 100 mg/L) were designed according to 3 × 3 factorial design. Our results suggested that the presence of F might antagonize the excretion of total As in urine, and As-F co-exposure led to severe pathological damage in brain tissue and reduced spatial learning and memory ability. At the same time, the experiments showed that As and F increased Beclin1 expression and LC3B ratio to activate autophagy; both P62 and Lamp2 expression were increased, suggesting that autophagy lysosomal degradation was blocked; SYN and JIP1 expression were significantly decreased, disrupting synaptic structure and function. Axonal autophagosome reverse transport regulation might be affected by combined As-F exposure, exacerbating neuronal synaptic damage and inducing neurotoxicity. Further analysis showed that there was an interaction between As and F exposure-induced changes in autolysosome-related proteins in the hippocampus, which showed antagonism, and the antagonism of the high As combined exposure groups were stronger than that of the low As combined exposure groups. In conclusion, our study showed that combined As and F exposure might induce reverse transport impairment of autophagy on axons, leading to autophagy defects, which in turn led to disruption of synaptic morphology and function, induced neurotoxicity, and there was an interaction between As and F, the type of its combined effect was antagonism.
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Affiliation(s)
- Qiuyi Zhao
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Weizhe Pan
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Jia Li
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Shengnan Yu
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Yan Liu
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Xiaoli Zhang
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China; Department of Microbiology Laboratory, Linfen Central Hospital, Linfen, China.
| | - Ruodi Qu
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Qian Zhang
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Ben Li
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Xiaoyan Yan
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
| | - Xuefeng Ren
- Department of Epidemiology and Environmental Health, School of Public Health and Health Professions, University at Buffalo, Buffalo, NY, USA; Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.
| | - Yulan Qiu
- Department of Toxicology, School of Public Health, Shanxi Medical University, Taiyuan, China.
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29
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Do methylenetetrahydrofolate dehydrogenase, cyclohydrolase, and formyltetrahydrofolate synthetase 1 polymorphisms modify changes in intelligence of school-age children in areas of endemic fluorosis? Chin Med J (Engl) 2022; 135:1846-1854. [PMID: 35838408 PMCID: PMC9521762 DOI: 10.1097/cm9.0000000000002062] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Excessive exposure to fluoride can reduce intelligence. Methylenetetrahydrofolate dehydrogenase, cyclohydrolase, and formyltetrahydrofolate synthetase 1 ( MTHFD1 ) polymorphisms have important roles in neurodevelopment. However, the association of MTHFD1 polymorphisms with children's intelligence changes in endemic fluorosis areas has been rarely explored. METHODS A cross-sectional study was conducted in four randomly selected primary schools in Tongxu County, Henan Province, from April to May in 2017. A total of 694 children aged 8 to 12 years were included in the study with the recruitment by the cluster sampling method. Urinary fluoride (UF) and urinary creatinine were separately determined using the fluoride ion-selective electrode and creatinine assay kit. Children were classified as the high fluoride group and control group according to the median of urinary creatinine-adjusted urinary fluoride (UF Cr ) level. Four loci of MTHFD1 were genotyped, and the Combined Raven's Test was used to evaluate children's intelligence quotient (IQ). Generalized linear model and multinomial logistic regression model were performed to analyze the associations between children's UF Cr level, MTHFD1 polymorphisms, and intelligence. The general linear model was used to explore the effects of gene-environment and gene-gene interaction on intelligence. RESULTS In the high fluoride group, children's IQ scores decreased by 2.502 when the UF Cr level increased by 1.0 mg/L (β = -2.502, 95% confidence interval [CI]:-4.411, -0.593), and the possibility for having "excellent" intelligence decreased by 46.3% (odds ratio = 0.537, 95% CI: 0.290, 0.994). Children with the GG genotype showed increased IQ scores than those with the AA genotype of rs11627387 locus in the high fluoride group ( P < 0.05). Interactions between fluoride exposure and MTHFD1 polymorphisms on intelligence were observed (Pinteraction < 0.05). CONCLUSION Our findings suggest that excessive fluoride exposure may have adverse effects on children's intelligence, and changes in children's intelligence may be associated with the interaction between fluoride and MTHFD1 polymorphisms.
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30
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Goodman CV, Bashash M, Green R, Song P, Peterson KE, Schnaas L, Mercado-García A, Martínez-Medina S, Hernández-Avila M, Martinez-Mier A, Téllez-Rojo MM, Hu H, Till C. Domain-specific effects of prenatal fluoride exposure on child IQ at 4, 5, and 6-12 years in the ELEMENT cohort. ENVIRONMENTAL RESEARCH 2022; 211:112993. [PMID: 35276192 PMCID: PMC9890727 DOI: 10.1016/j.envres.2022.112993] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/13/2022] [Accepted: 02/19/2022] [Indexed: 05/17/2023]
Abstract
OBJECTIVE Prenatal exposure to fluoride has been associated with adverse neurodevelopmental outcomes. However, the neuropsychological profile of fluoride's developmental neurotoxicity at low levels and the stability of this relationship across childhood has not been characterized. We investigated the longitudinal and domain specific effect of prenatal fluoride exposure on IQ among children ages 4, 5, and 6-12 years in the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort. METHODS We measured the average of maternal urinary fluoride at each trimester of pregnancy adjusted for creatinine (MUFCRE). Children were administered the McCarthy Scales of Children's Abilities at ages 4 (N = 386) and 5 (N = 308), and the Wechsler Abbreviated Scale of Intelligence at age 6-12 (N = 278). We used generalized estimating equation (GEE) models to estimate the population averaged effect of MUFCRE concentration on longitudinal General Cognitive Index (GCI)/Full-Scale IQ (FSIQ), Verbal IQ (VIQ), and Performance IQ (PIQ) scores (N = 348). We tested for possible interactions between MUFCRE and child sex as well as for MUFCRE and time point on children's IQ. All models controlled for relevant available covariates. RESULTS The mean/median MUFCRE concentration was 0.90/0.83 mg/L (SD = 0.39; IQR, 0.64-1.11 mg/L). A 0.5 mg/L increase in MUFCRE predicted an average 2.12-point decrease in GCI/FSIQ (95% CI: -3.49, -0.75) and 2.63-point decrease in PIQ (95% CI: -3.87, -1.40). MUFCRE was marginally associated with VIQ across time (B = -1.29, 95% CI: -2.60, 0.01). No interactions between MUFCRE and child sex or MUFCRE and time were observed. CONCLUSION The negative association between prenatal fluoride exposure and longitudinal IQ was driven by decrements in non-verbal intelligence (i.e. PIQ), suggesting that visual-spatial and perceptual reasoning abilities may be more impacted by prenatal fluoride exposure as compared to verbal abilities.
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Affiliation(s)
- Carly V Goodman
- Faculty of Health, York University, Toronto, Ontario, Canada
| | - Morteza Bashash
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Rivka Green
- Faculty of Health, York University, Toronto, Ontario, Canada
| | - Peter Song
- School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Karen E Peterson
- School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | | | | | | | | | | | | | - Howard Hu
- Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Christine Till
- Faculty of Health, York University, Toronto, Ontario, Canada
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31
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Goodman CV, Hall M, Green R, Chevrier J, Ayotte P, Martinez-Mier EA, McGuckin T, Krzeczkowski J, Flora D, Hornung R, Lanphear B, Till C. Iodine Status Modifies the Association between Fluoride Exposure in Pregnancy and Preschool Boys' Intelligence. Nutrients 2022; 14:2920. [PMID: 35889877 PMCID: PMC9319869 DOI: 10.3390/nu14142920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 07/11/2022] [Accepted: 07/13/2022] [Indexed: 12/07/2022] Open
Abstract
In animal studies, the combination of in utero fluoride exposure and low iodine has greater negative effects on offspring learning and memory than either alone, but this has not been studied in children. We evaluated whether the maternal urinary iodine concentration (MUIC) modifies the association between maternal urinary fluoride (MUF) and boys' and girls' intelligence. We used data from 366 mother-child dyads in the Maternal-Infant Research on Environmental Chemicals Study. We corrected trimester-specific MUF and MUIC for creatinine, and averaged them to yield our exposure variables (MUFCRE, mg/g; MUICCRE, µg/g). We assessed children's full-scale intelligence (FSIQ) at 3 to 4 years. Using multiple linear regression, we estimated a three-way interaction between MUFCRE, MUICCRE, and child sex on FSIQ, controlling for covariates. The MUICCRE by MUFCRE interaction was significant for boys (p = 0.042), but not girls (p = 0.190). For boys whose mothers had low iodine, a 0.5 mg/g increase in MUFCRE was associated with a 4.65-point lower FSIQ score (95% CI: -7.67, -1.62). For boys whose mothers had adequate iodine, a 0.5 mg/g increase in MUFCRE was associated with a 2.95-point lower FSIQ score (95% CI: -4.77, -1.13). These results suggest adequate iodine intake during pregnancy may minimize fluoride's neurotoxicity in boys.
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Affiliation(s)
- Carly V. Goodman
- Department of Psychology, York University, Toronto, ONT M3J 1P3, Canada; (C.V.G.); (M.H.); (R.G.); (T.M.); (J.K.); (D.F.)
| | - Meaghan Hall
- Department of Psychology, York University, Toronto, ONT M3J 1P3, Canada; (C.V.G.); (M.H.); (R.G.); (T.M.); (J.K.); (D.F.)
| | - Rivka Green
- Department of Psychology, York University, Toronto, ONT M3J 1P3, Canada; (C.V.G.); (M.H.); (R.G.); (T.M.); (J.K.); (D.F.)
| | - Jonathan Chevrier
- Department of Epidemiology, Biostatistics, and Occupational Health, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC H3A 1G1, Canada;
| | - Pierre Ayotte
- Département de Médecine Sociale et Préventive, Faculté de Médecine, Université Laval, Québec, QC G1V 0A6, Canada;
| | - Esperanza Angeles Martinez-Mier
- Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, Indianapolis, IN 46202, USA;
| | - Taylor McGuckin
- Department of Psychology, York University, Toronto, ONT M3J 1P3, Canada; (C.V.G.); (M.H.); (R.G.); (T.M.); (J.K.); (D.F.)
| | - John Krzeczkowski
- Department of Psychology, York University, Toronto, ONT M3J 1P3, Canada; (C.V.G.); (M.H.); (R.G.); (T.M.); (J.K.); (D.F.)
| | - David Flora
- Department of Psychology, York University, Toronto, ONT M3J 1P3, Canada; (C.V.G.); (M.H.); (R.G.); (T.M.); (J.K.); (D.F.)
| | - Richard Hornung
- Pediatrics and Environmental Health, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA;
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC V5A 1S6, Canada;
| | - Christine Till
- Department of Psychology, York University, Toronto, ONT M3J 1P3, Canada; (C.V.G.); (M.H.); (R.G.); (T.M.); (J.K.); (D.F.)
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Saad H, Escoube R, Babajko S, Houari S. Fluoride Intake Through Dental Care Products: A Systematic Review. FRONTIERS IN ORAL HEALTH 2022; 3:916372. [PMID: 35757442 PMCID: PMC9231728 DOI: 10.3389/froh.2022.916372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 05/04/2022] [Indexed: 11/24/2022] Open
Abstract
Fluoride (F) is added to many dental care products as well as in drinking water to prevent dental decay. However, recent data associating exposure to F with some developmental defects with consequences in many organs raise concerns about its daily use for dental care. This systematic review aimed to evaluate the contribution of dental care products with regard to overall F intake through drinking water and diet with measurements of F excretion in urine used as a suitable biomarker. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using keywords related to chronic exposure to F in the human population with measurements of F levels in body fluids, 1,273 papers published between 1995 and 2021 were screened, and 28 papers were finally included for data extraction concerning daily F intake. The contribution of dental care products, essentially by toothbrushing with kinds of toothpaste containing F, was 38% in the mean regardless of the F concentrations in drinking water. There was no correlation between F intake through toothpaste and age, nor with F levels in water ranging from 0.3 to 1.5 mg/L. There was no correlation between F intake and urinary F excretion levels despite an increase in its content in urine within hours following exposure to dental care products (toothpastes, varnishes, or other dental care products). The consequences of exposure to F on health are discussed in the recent context of its suspected toxicity reported in the literature. The conclusions of the review aim to provide objective messages to patients and dental professionals worried about the use of F-containing materials or products to prevent initial caries or hypomineralized enamel lesions, especially for young children.
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Affiliation(s)
- Hanan Saad
- Laboratory of Molecular Oral Physiopathology, Centre de Recherche des Cordeliers, INSERM, Université Paris Cité, Sorbonne Université, Paris, France
- AP-HP, Dental Medicine Department, Pitié-Salpétrière Hospital, GHN-Université Paris Cité, Paris, France
| | - Raphaëlle Escoube
- Laboratoire de Géologie de Lyon, UM R5276, CNRS, Université Lyon 1, École Normale Supérieure de Lyon 46, Lyon, France
| | - Sylvie Babajko
- Laboratory of Molecular Oral Physiopathology, Centre de Recherche des Cordeliers, INSERM, Université Paris Cité, Sorbonne Université, Paris, France
- *Correspondence: Sylvie Babajko
| | - Sophia Houari
- Laboratory of Molecular Oral Physiopathology, Centre de Recherche des Cordeliers, INSERM, Université Paris Cité, Sorbonne Université, Paris, France
- AP-HP, Dental Medicine Department, Pitié-Salpétrière Hospital, GHN-Université Paris Cité, Paris, France
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Adkins EA, Yolton K, Strawn JR, Lippert F, Ryan PH, Brunst KJ. Fluoride exposure during early adolescence and its association with internalizing symptoms. ENVIRONMENTAL RESEARCH 2022; 204:112296. [PMID: 34755609 PMCID: PMC8725192 DOI: 10.1016/j.envres.2021.112296] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/19/2021] [Accepted: 10/25/2021] [Indexed: 05/14/2023]
Abstract
BACKGROUND Early, chronic, low-level fluoride exposure has been linked to attention-deficit hyperactivity disorder (ADHD) and learning deficits in children. Rodent studies suggest a link between fluoride exposure and internalizing behaviors. No human studies have examined the impact of fluoride on internalizing behaviors during adolescence. OBJECTIVE Evaluate the relationship between urinary fluoride and early adolescent internalizing symptoms in the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). METHODS Participants in CCAAPS provided non-fasting spot urine samples at age 12 years (n = 286). Urine samples were analyzed using a microdiffusion method to determine childhood urinary fluoride (CUF) concentrations and were log-transformed for analyses. Caregivers of CCAAPS participants completed the Behavior Assessment System for Children-2 (BASC-2) at the age 12 study visit to assess internalizing symptoms (e.g., anxiety, depression, somatization), and a composite score of the three domains; T-scores ≥ 60 were used to identify adolescents in a clinically "at-risk" range. Race, age of the adolescent, household income, maternal age at birth, caregiver depression, caregiver-child relationships, and age 12-year serum cotinine concentrations were considered covariates in regression models. Sex-specific effects of fluoride exposures were investigated through the inclusion of interaction terms. RESULTS Higher CUF concentrations were significantly associated with increased somatization (β = 3.64, 95% CI 0.49, 6.81) and internalizing composite T-scores in a clinically "at-risk" range (OR = 2.9, 95% CI 1.24, 6.9). Compared to females, males with higher CUF concentrations had more internalizing (pinteraction = 0.04) and somatization symptoms (pinteraction = 0.02) and were nearly seven times more likely to exhibit "at-risk" internalizing symptomology. CUF concentrations were not significantly associated with depression or anxiety symptoms. CONCLUSIONS This is the first study to link fluoride exposure and internalizing symptoms, specifically somatization. Somatization represents an interface of physical and psychological health. Continued follow-up will help shed light on the sex-specific relationship between fluoride and mental health and the role of somatization.
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Affiliation(s)
- Emily A Adkins
- Department of Environmental and Public Health Sciences, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH, 45267, USA
| | - Kimberly Yolton
- Division of General and Community Pediatrics, Department of Pediatrics, Cincinnati Children's Hospital Medical Center and the University of Cincinnati College of Medicine, 3333 Burnet Avenue, MLC, 5041, Cincinnati, OH, 45229, USA
| | - Jeffrey R Strawn
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, 260 Stetson Street, Cincinnati, OH, 45219, USA
| | - Frank Lippert
- Department of Cariology, Operative Dentistry, and Dental Public Health, Oral Health Research Institute, Indiana University School of Dentistry, 415 Lansing Street, Indianapolis, IN, 46202, USA
| | - Patrick H Ryan
- Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH, 45229, USA
| | - Kelly J Brunst
- Department of Environmental and Public Health Sciences, University of Cincinnati, 160 Panzeca Way, Cincinnati, OH, 45267, USA.
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Grandjean P, Hu H, Till C, Green R, Bashash M, Flora D, Tellez-Rojo MM, Song PX, Lanphear B, Budtz-Jørgensen E. A Benchmark Dose Analysis for Maternal Pregnancy Urine-Fluoride and IQ in Children. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2022; 42:439-449. [PMID: 34101876 PMCID: PMC9831700 DOI: 10.1111/risa.13767] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 04/30/2021] [Accepted: 05/22/2021] [Indexed: 05/11/2023]
Abstract
As a guide to establishing a safe exposure level for fluoride exposure in pregnancy, we applied benchmark dose modeling to data from two prospective birth cohort studies. We included mother-child pairs from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort in Mexico and the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort in Canada. Maternal urinary fluoride concentrations (U-F, in mg/L, creatinine-adjusted) were measured in urine samples obtained during pregnancy. Children were assessed for intelligence quotient (IQ) at age 4 (n = 211) and between six and 12 years (n = 287) in the ELEMENT cohort, and three to four years (n = 407) in the MIREC cohort. We calculated covariate-adjusted regression coefficients and their standard errors to assess the association of maternal U-F concentrations with children's IQ measures. Assuming a benchmark response of 1 IQ point, we derived benchmark concentrations (BMCs) and benchmark concentration levels (BMCLs). No deviation from linearity was detected in the dose-response relationships, but boys showed lower BMC values than girls. Using a linear slope for the joint cohort data, the BMC for maternal U-F associated with a 1-point decrease in IQ scores was 0.31 mg/L (BMCL, 0.19 mg/L) for the youngest boys and girls in the two cohorts, and 0.33 mg/L (BMCL, 0.20 mg/L) for the MIREC cohort and the older ELEMENT children. Thus, the joint data show a BMCL in terms of the adjusted U-F concentrations in the pregnant women of approximately 0.2 mg/L. These results can be used to guide decisions on preventing excess fluoride exposure in pregnant women.
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Affiliation(s)
- Philippe Grandjean
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Department of Public Health, University of Southern Denmark, Odense, Denmark
- Address correspondence to Philippe Grandjean, Environmental Medicine, University of Southern Denmark, J.B. Winslows vej 17A, 5000 Odense C, Denmark; tel: +45 6550 3769; fax: +45 6591 1458;
| | - Howard Hu
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Rivka Green
- Faculty of Health, York University, Ontario, Canada
| | - Morteza Bashash
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - David Flora
- Faculty of Health, York University, Ontario, Canada
| | - Martha Maria Tellez-Rojo
- Centro de Investigacion en Salud Poblacional, Instituto Nacional de Salud Publica, Cuernavaca, Morelos, Mexico
| | - Peter X.K. Song
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, British Columbia, Canada
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Vitamin D Supplementation in Exclusively Breastfed Infants Is Associated with Alterations in the Fecal Microbiome. Nutrients 2022; 14:nu14010202. [PMID: 35011077 PMCID: PMC8747039 DOI: 10.3390/nu14010202] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 12/24/2021] [Accepted: 12/30/2021] [Indexed: 02/01/2023] Open
Abstract
Breastfeeding and introduction of solid food are the two major components of infant feeding practices that influence gut microbiota composition in early infancy. However, it is unclear whether additional factors influence the microbiota of infants either exclusively breastfed or not breastfed. We obtained 194 fecal samples from infants at 3–9 months of age, extracted DNA, and sequenced the V4 region of the 16S rRNA gene. Feeding practices and clinical information were collected by questionnaire and abstraction of birth certificates. The gut microbiota of infants who were exclusively breastfed displayed significantly lower Shannon diversity (p-adjust < 0.001) and different gut microbiota composition compared to infants who were not breastfed (p-value = 0.001). Among the exclusively breastfed infants, recipients of vitamin D supplements displayed significantly lower Shannon diversity (p-adjust = 0.007), and different gut microbiota composition structure than non-supplemented, breastfed infants (p-value = 0.02). MaAslin analysis identified microbial taxa that associated with breastfeeding and vitamin D supplementation. Breastfeeding and infant vitamin D supplement intake play an important role in shaping infant gut microbiota.
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Dietary fluoride intake during pregnancy and neurodevelopment in toddlers: A prospective study in the progress cohort. Neurotoxicology 2021; 87:86-93. [PMID: 34478773 PMCID: PMC8595627 DOI: 10.1016/j.neuro.2021.08.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/03/2021] [Accepted: 08/28/2021] [Indexed: 12/21/2022]
Abstract
Foods and beverages provide a source of fluoride exposure in Mexico. While high fluoride concentrations are neurotoxic, recent research suggests that exposures within the optimal range may also pose a risk to the developing brain. This prospective study examined whether dietary fluoride intake during pregnancy is associated with toddlers' neurodevelopment in 103 mother-child pairs from the PROGRESS cohort in Mexico City. Food and beverage fluoride intake was assessed in trimesters 2 and 3 using a food frequency questionnaire and Mexican tables of fluoride content. We used the Bayley-III to evaluate cognitive, motor, and language outcomes at 12 and 24 months of age. Adjusted linear regression models were generated for each neurodevelopment assessment time point (12 and 24 months). Mixed-effects models were used to consider a repeated measurement approach. Interactions between maternal fluoride intake and child sex on neurodevelopmental outcomes were tested. Median (IQR) dietary fluoride intake during pregnancy was 1.01 mg/d (0.73, 1.32). Maternal fluoride intake was not associated with cognitive, language, or motor outcomes collapsing across boys and girls. However, child sex modified the association between maternal fluoride intake and cognitive outcome (p interaction term = 0.06). A 0.5 mg/day increase in overall dietary fluoride intake was associated with a 3.50-point lower cognitive outcome in 24-month old boys (95 % CI: -6.58, -0.42); there was no statistical association with girls (β = 0.07, 95 % CI: -2.37, 2.51), nor on the cognitive outcome at 12-months of age. Averaging across the 12- and 24-month cognitive outcomes using mixed-effects models revealed a similar association: a 0.5 mg/day increase in overall dietary fluoride intake was associated with a 3.46-point lower cognitive outcome in boys (95 % CI: -6.23, -0.70). These findings suggest that the development of nonverbal abilities in males may be more vulnerable to prenatal fluoride exposure than language or motor abilities, even at levels within the recommended intake range.
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Wang S, Zhao Q, Li G, Wang M, Liu H, Yu X, Chen J, Li P, Dong L, Zhou G, Cui Y, Wang M, Liu L, Wang A. The cholinergic system, intelligence, and dental fluorosis in school-aged children with low-to-moderate fluoride exposure. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 228:112959. [PMID: 34808511 DOI: 10.1016/j.ecoenv.2021.112959] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/27/2021] [Accepted: 10/31/2021] [Indexed: 06/13/2023]
Abstract
Disruption of cholinergic neurotransmission can affect cognition, but little is known about whether low-to-moderate fluoride exposure affects cholinergic system and its effect on the prevalence of dental fluorosis (DF) and intelligence quotient (IQ). A cross-sectional study was conducted to explore the associations of moderate fluoride exposure and cholinergic system in relation to children's DF and IQ. We recruited 709 resident children in Tianjin, China. Ion selective electrode method was used to detect fluoride concentrations in water and urine. Cholinergic system was assessed by the detection of choline acetyltransferase (ChAT), acetylcholinesterase (AChE) and acetylcholine (ACh) levels in serum. Compared with children in the first quartile, those in fourth quartile the risk of either developing DF or IQ < 120 increased by 19% and 20% for water and urinary fluoride. The risk of having both increased by 58% and 62% in third and fourth quartile for water fluoride, 52% and 65% for urinary fluoride. Water fluoride concentrations were positively associated with AChE and negatively associated with ChAT and ACh, trends were same for urinary fluoride except for ACh. The risk of either developing DF or having non-high intelligence rose by 22% (95%CI: 1.07%, 1.38%) for the fourth quartile than those in the first quartile of AChE, for having the both, the risk was 1.27 (95%CI: 1.07, 1.50), 1.37 (95%CI: 1.17, 1.62) and 1.44 (95%CI: 1.23, 1.68) in second, third and fourth quartiles. The mediation proportion by AChE between water fluoride and either developing DF or IQ < 120 was 15.7%. For both to exist, the proportion was 6.7% and 7.2% for water and urinary fluoride. Our findings suggest low-to-moderate fluoride exposure was associated with dysfunction of cholinergic system for children. AChE may partly mediate the prevalence of DF and lower probability of having superior and above intelligence.
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Affiliation(s)
- Sumei Wang
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Qian Zhao
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Gaochun Li
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Mengwei Wang
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Hongliang Liu
- Tianjin Centers for Disease Control and Prevention, Tianjin, PR China
| | - Xingchen Yu
- Department of Epidemiology and Biostatistics, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Jingwen Chen
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Pei Li
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Lixin Dong
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Guoyu Zhou
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Yushan Cui
- Tianjin Centers for Disease Control and Prevention, Tianjin, PR China
| | - Mengru Wang
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Li Liu
- Department of Epidemiology and Biostatistics, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
| | - Aiguo Wang
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China; Key Laboratory of Environment and Health, Ministry of Education and Ministry of Environmental Protection, State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
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Yu X, Xia L, Zhang S, Zhou G, Li Y, Liu H, Hou C, Zhao Q, Dong L, Cui Y, Zeng Q, Wang A, Liu L. Fluoride exposure and children's intelligence: Gene-environment interaction based on SNP-set, gene and pathway analysis, using a case-control design based on a cross-sectional study. ENVIRONMENT INTERNATIONAL 2021; 155:106681. [PMID: 34098334 DOI: 10.1016/j.envint.2021.106681] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 05/25/2021] [Accepted: 05/27/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Excessive fluoride exposure has been associated with intelligence loss, but little is known about gene-fluoride interactions on intelligence at SNP-set, gene and pathway level. OBJECTIVES Here we conducted a population-based study in Chinese school-aged children to estimate the associations of fluoride from internal and external exposures with intelligence as well as to explore the gene-fluoride interactions on intelligence at SNP-set, gene and neurodevelopmental pathway level. METHODS A total of 952 resident children aged 7 to 13 were included in the current study. The fluoride contents in drinking water, urine, hair and nail were measured using the ion-selective electrode method. LASSO Binomial regression was conducted to screen the intelligence-related SNP-set. The gene-fluoride interactions at gene and pathway levels were detected by the Adaptive Rank Truncated Product method. RESULTS The probability of high intelligence was inversely correlated with fluoride contents in water, urine, hair and nail (all P < 0.001). The SNP-set based on rs3788319, rs1879417, rs57377675, rs11556505 and rs7187776 was related to high intelligence (P = 0.001) alone and by interaction with water, urinary and hair fluoride (P = 0.030, 0.040, 0.010), separately. In gene level, CLU and TOMM40 interacted with hair fluoride (both P = 0.017) on intelligence. In pathway level, Alzheimer disease pathway, metabolic pathway, signal transduction pathway, sphingolipid signaling pathway and PI3K-AKT signaling pathway interacted with fluoride on intelligence in men. CONCLUSIONS Our study suggests that fluoride is inversely associated with intelligence. Moreover, the interactions of fluoride with mitochondrial function-related SNP-set, genes and pathways may also be involved in high intelligence loss.
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Affiliation(s)
- Xingchen Yu
- Department of Epidemiology and Biostatistics, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Lu Xia
- Department of Epidemiology and Biostatistics, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Shun Zhang
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Guoyu Zhou
- Department of Environment Health, School of Public Health, Zhengzhou University, Zhengzhou, Henan 450001, PR China
| | - Yonggang Li
- Tianjin Baodi District Centers for Disease Control and Prevention, Tianjin, PR China
| | - Hongliang Liu
- Tianjin Centers for Disease Control and Prevention, Tianjin, PR China
| | - Changchun Hou
- Tianjin Centers for Disease Control and Prevention, Tianjin, PR China
| | - Qian Zhao
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Lixin Dong
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China
| | - Yushan Cui
- Tianjin Centers for Disease Control and Prevention, Tianjin, PR China
| | - Qiang Zeng
- Tianjin Centers for Disease Control and Prevention, Tianjin, PR China
| | - Aiguo Wang
- Department of Occupational and Environmental Health, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
| | - Li Liu
- Department of Epidemiology and Biostatistics, Ministry of Education Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, PR China.
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Poornima P, Krithikadatta J, Ponraj RR, Velmurugan N, Kishen A. Biofilm formation following chitosan-based varnish or chlorhexidine-fluoride varnish application in patients undergoing fixed orthodontic treatment: a double blinded randomised controlled trial. BMC Oral Health 2021; 21:465. [PMID: 34556107 PMCID: PMC8459499 DOI: 10.1186/s12903-021-01805-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 08/12/2021] [Indexed: 11/17/2022] Open
Abstract
Background Orthodontic treatment poses an increased risk of plaque accumulation and demineralisation of enamel leading to white spot lesion around the brackets. This parallel arm trial aims to assess the degree of bacterial plaque formation adjacent to orthodontic brackets, following the application of a chitosan-based varnish or chlorhexidene-fluoride varnish. Methods A total of 200 teeth from 20 patients undergoing fixed orthodontic therapy were assessed and biofilm formation around the brackets were recorded using the Bonded Bracket Index (Plaque index) at baseline and weekly for 6 weeks. The bacterial count and plaque pH at corresponding weekly intervals were also recorded. Following bracket bonding, the patients were cluster randomised to receive chitosan-based varnish-CHS (UNO Gel Bioschell, Germiphene corp., Brantford, Canada) or chlorhexidine-fluoride varnish-CFV (Cervitec F, Ivoclar Vivadent, Schaan, Liechtenstein) every week on the representative teeth respectively. BBI proportions were compared between groups at all time intervals using Chi square test. Mean plaque bacterial count and plaque pH were compared using Mann Whitney U test and Tukey’s HSD test respectively. Results Baseline characteristics were similar between the groups: Mean age was CHS = 23 and CFV = 21; male to female ratio was CHS = 5/5, CFV = 7/3. At the end of 6 weeks, chitosan-based varnish performed equal to chlorhexidine-fluoride varnish (P > 0.05) with 98% and 95% of teeth with acceptable scores respectively. The plaque bacterial count significantly reduced at 6 weeks for both varnish compared to the baseline; The value for CHS was 0.43 ± 0.4 × 104 and CFV was 0.77 ± 0.64 × 104 CFU (P < 0.05), with no difference between both the varnishes. Both varnishes had no effect on the plaque pH that remained neutral. Conclusion This trial showed that both chitosan-based varnish and chlorhexidine-fluoride varnish reduced bacterial count, while the plaque pH remained neutral over a period of six weeks in patients undergoing fixed orthodontic therapy. The anti-plaque effects of the natural biopolymeric chitosan-based varnish was similar to that of chlorhexidine-fluoride varnish, a known chemotherapeutic agent. Registration: This trial protocol was registered with https://www.ctri.nic.in (CTRI/2019/05/018896). (Date of registration 02/05/2019). Protocol: The protocol was not published before trial commencement.
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Affiliation(s)
- Preethi Poornima
- Department of Conservative Dentistry and Endodontics, Faculty of Dentistry, MAHER, Chennai, India
| | | | | | | | - Anil Kishen
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.
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40
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Farmus L, Till C, Green R, Hornung R, Martinez Mier EA, Ayotte P, Muckle G, Lanphear BP, Flora DB. Critical windows of fluoride neurotoxicity in Canadian children. ENVIRONMENTAL RESEARCH 2021; 200:111315. [PMID: 34051202 PMCID: PMC9884092 DOI: 10.1016/j.envres.2021.111315] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/28/2021] [Accepted: 05/07/2021] [Indexed: 05/08/2023]
Abstract
BACKGROUND Fluoride has been associated with IQ deficits during early brain development, but the period in which children are most sensitive is unknown. OBJECTIVE We assessed effects of fluoride on IQ scores across prenatal and postnatal exposure windows. METHODS We used repeated exposures from 596 mother-child pairs in the Maternal-Infant Research on Environmental Chemicals pregnancy and birth cohort. Fluoride was measured in urine (mg/L) collected from women during pregnancy and in their children between 1.9 and 4.4 years; urinary fluoride was adjusted for specific gravity. We estimated infant fluoride exposure (mg/day) using water fluoride concentration and duration of formula-feeding over the first year of life. Intelligence was assessed at 3-4 years using the Wechsler Preschool and Primary Scale of Intelligence-III. We used generalized estimating equations to examine the associations between fluoride exposures and IQ, adjusting for covariates. We report results based on standardized exposures given their varying units of measurement. RESULTS The association between fluoride and performance IQ (PIQ) significantly differed across prenatal, infancy, and childhood exposure windows collapsing across child sex (p = .001). The strongest association between fluoride and PIQ was during the prenatal window, B = -2.36, 95% CI: -3.63, -1.08; the association was also significant during infancy, B = -2.11, 95% CI: -3.45, -0.76, but weaker in childhood, B = -1.51, 95% CI: -2.90, -0.12. Within sex, the association between fluoride and PIQ significantly differed across the three exposure windows (boys: p = .01; girls: p = .01); among boys, the strongest association was during the prenatal window, B = -3.01, 95% CI: -4.60, -1.42, whereas among girls, the strongest association was during infancy, B = -2.71, 95% CI: -4.59, -0.83. Full-scale IQ estimates were weaker than PIQ estimates for every window. Fluoride was not significantly associated with Verbal IQ across any exposure window. CONCLUSION Associations between fluoride exposure and PIQ differed based on timing of exposure. The prenatal window may be critical for boys, whereas infancy may be a critical window for girls.
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Affiliation(s)
- Linda Farmus
- Faculty of Health, York University, Ontario, Canada
| | | | - Rivka Green
- Faculty of Health, York University, Ontario, Canada
| | - Richard Hornung
- Pediatrics and Environmental Health, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - E Angeles Martinez Mier
- Department of Cardiology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, Indiana, USA
| | - Pierre Ayotte
- Centre de Recherche Du CHU de Québec, Université Laval, Québec, Canada; Department of Social and Preventive Medicine, Laval University, Quebec, Canada
| | - Gina Muckle
- Centre de Recherche Du CHU de Québec, Université Laval, Québec, Canada; School of Psychology, Laval University, Quebec, Canada
| | - Bruce P Lanphear
- Faculty of Health Sciences, Simon Fraser University, British Columbia, Canada; Child & Family Research Institute, BC Children's Hospital, University of British Columbia, British Columbia, Canada
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41
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Guth S, Hüser S, Roth A, Degen G, Diel P, Edlund K, Eisenbrand G, Engel KH, Epe B, Grune T, Heinz V, Henle T, Humpf HU, Jäger H, Joost HG, Kulling SE, Lampen A, Mally A, Marchan R, Marko D, Mühle E, Nitsche MA, Röhrdanz E, Stadler R, van Thriel C, Vieths S, Vogel RF, Wascher E, Watzl C, Nöthlings U, Hengstler JG. Contribution to the ongoing discussion on fluoride toxicity. Arch Toxicol 2021; 95:2571-2587. [PMID: 34095968 PMCID: PMC8241794 DOI: 10.1007/s00204-021-03072-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/04/2021] [Indexed: 01/17/2023]
Abstract
Since the addition of fluoride to drinking water in the 1940s, there have been frequent and sometimes heated discussions regarding its benefits and risks. In a recently published review, we addressed the question if current exposure levels in Europe represent a risk to human health. This review was discussed in an editorial asking why we did not calculate benchmark doses (BMD) of fluoride neurotoxicity for humans. Here, we address the question, why it is problematic to calculate BMDs based on the currently available data. Briefly, the conclusions of the available studies are not homogeneous, reporting negative as well as positive results; moreover, the positive studies lack control of confounding factors such as the influence of well-known neurotoxicants. We also discuss the limitations of several further epidemiological studies that did not meet the inclusion criteria of our review. Finally, it is important to not only focus on epidemiological studies. Rather, risk analysis should consider all available data, including epidemiological, animal, as well as in vitro studies. Despite remaining uncertainties, the totality of evidence does not support the notion that fluoride should be considered a human developmental neurotoxicant at current exposure levels in European countries.
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Affiliation(s)
- Sabine Guth
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Stephanie Hüser
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Angelika Roth
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Gisela Degen
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Patrick Diel
- Department of Molecular and Cellular Sports Medicine, Institute of Cardiovascular Research and Sports Medicine, German Sport University Cologne, Cologne, Germany
| | - Karolina Edlund
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | | | - Karl-Heinz Engel
- Department of General Food Technology, School of Life Sciences, TU Munich, Freising, Germany
| | - Bernd Epe
- Institute of Pharmacy and Biochemistry, University of Mainz, Mainz, Germany
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany
| | - Volker Heinz
- German Institute of Food Technologies (DIL), Quakenbrück, Germany
| | - Thomas Henle
- Department of Food Chemistry, TU Dresden, Dresden, Germany
| | - Hans-Ulrich Humpf
- Institute of Food Chemistry, Westfälische Wilhelms-Universität Münster, Münster, Germany
| | - Henry Jäger
- Institute of Food Technology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Hans-Georg Joost
- Department of Experimental Diabetology, German Institute of Human Nutrition (DIfE), Nuthetal, Germany
| | - Sabine E Kulling
- Department of Safety and Quality of Fruit and Vegetables, Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Karlsruhe, Germany
| | - Alfonso Lampen
- Department of Food Safety, Bundesinstitut für Risikobewertung (BfR), Berlin, Germany
| | - Angela Mally
- Department of Toxicology, University of Würzburg, Würzburg, Germany
| | - Rosemarie Marchan
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Doris Marko
- Department of Food Chemistry and Toxicology, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Eva Mühle
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Michael A Nitsche
- Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany.,Department of Neurology, University Medical Hospital Bergmannsheil, Ruhr-University, Bochum, Germany
| | - Elke Röhrdanz
- Department of Experimental Pharmacology and Toxicology, Federal Institute for Drugs and Medical Devices (BfArM), Bonn, Germany
| | - Richard Stadler
- Institute of Food Safety and Analytic Sciences, Nestlé Research Centre, Lausanne, Switzerland
| | - Christoph van Thriel
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | | | - Rudi F Vogel
- Lehrstuhl für Technische Mikrobiologie, TU Munich, Freising, Germany
| | - Edmund Wascher
- Department of Ergonomics, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Carsten Watzl
- Department of Immunology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany
| | - Ute Nöthlings
- Department of Nutrition and Food Sciences, Nutritional Epidemiology, Rheinische Friedrich-Wilhelms University Bonn, Bonn, Germany.
| | - Jan G Hengstler
- Department of Toxicology, Leibniz Research Centre for Working Environment and Human Factors (IfADo), Dortmund, Germany.
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Han J, Kiss L, Mei H, Remete AM, Ponikvar-Svet M, Sedgwick DM, Roman R, Fustero S, Moriwaki H, Soloshonok VA. Chemical Aspects of Human and Environmental Overload with Fluorine. Chem Rev 2021; 121:4678-4742. [PMID: 33723999 PMCID: PMC8945431 DOI: 10.1021/acs.chemrev.0c01263] [Citation(s) in RCA: 131] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Indexed: 12/24/2022]
Abstract
Over the last 100-120 years, due to the ever-increasing importance of fluorine-containing compounds in modern technology and daily life, the explosive development of the fluorochemical industry led to an enormous increase of emission of fluoride ions into the biosphere. This made it more and more important to understand the biological activities, metabolism, degradation, and possible environmental hazards of such substances. This comprehensive and critical review focuses on the effects of fluoride ions and organofluorine compounds (mainly pharmaceuticals and agrochemicals) on human health and the environment. To give a better overview, various connected topics are also discussed: reasons and trends of the advance of fluorine-containing pharmaceuticals and agrochemicals, metabolism of fluorinated drugs, withdrawn fluorinated drugs, natural sources of organic and inorganic fluorine compounds in the environment (including the biosphere), sources of fluoride intake, and finally biomarkers of fluoride exposure.
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Affiliation(s)
- Jianlin Han
- Jiangsu
Co-Innovation Center of Efficient Processing and Utilization of Forest
Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Loránd Kiss
- University
of Szeged, Institute of Pharmaceutical Chemistry
and Interdisciplinary Excellence Centre, Eötvös u. 6, 6720 Szeged, Hungary
| | - Haibo Mei
- Jiangsu
Co-Innovation Center of Efficient Processing and Utilization of Forest
Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Attila Márió Remete
- University
of Szeged, Institute of Pharmaceutical Chemistry
and Interdisciplinary Excellence Centre, Eötvös u. 6, 6720 Szeged, Hungary
| | - Maja Ponikvar-Svet
- Department
of Inorganic Chemistry and Technology, Jožef
Stefan Institute, Jamova
cesta 39, 1000 Ljubljana, Slovenia
| | - Daniel Mark Sedgwick
- Departamento
de Química Orgánica, Universidad
de Valencia, 46100 Burjassot, Valencia Spain
| | - Raquel Roman
- Departamento
de Química Orgánica, Universidad
de Valencia, 46100 Burjassot, Valencia Spain
| | - Santos Fustero
- Departamento
de Química Orgánica, Universidad
de Valencia, 46100 Burjassot, Valencia Spain
| | - Hiroki Moriwaki
- Hamari
Chemicals Ltd., 1-19-40, Nankokita, Suminoe-ku, Osaka 559-0034, Japan
| | - Vadim A. Soloshonok
- Department
of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, 20018 San Sebastian, Spain
- IKERBASQUE,
Basque Foundation for Science, 48011 Bilbao, Spain
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Mondal P, Shaw P, Dey Bhowmik A, Bandyopadhyay A, Sudarshan M, Chakraborty A, Chattopadhyay A. Combined effect of arsenic and fluoride at environmentally relevant concentrations in zebrafish (Danio rerio) brain: Alterations in stress marker and apoptotic gene expression. CHEMOSPHERE 2021; 269:128678. [PMID: 33127104 DOI: 10.1016/j.chemosphere.2020.128678] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 06/11/2023]
Abstract
Arsenic and fluoride are two naturally occurring toxicants to which various organisms including a major part of the human populations are co-exposed to. However, interactions between them inside body are quite complicated and needs proper evaluation. Inconclusive reports regarding their combined effects on brain prompted us to conduct this study where we investigated their individual as well as combined effects on female zebrafish brain at environmentally relevant concentrations (50 μgL-1 arsenic trioxide and 15 mgL-1 sodium fluoride) after different time intervals (15, 30 and 60 days). Persistent near-basal level of GSH, least increased MDA content and catalase activity portrayed arsenic and fluoride co-exposure as less toxic which was corroborated with far less damage caused in the histoarchitecture of optic tectum region in midbrain. Stress-responsive genes viz., Nrf2 and Hsp70 were overexpressed after individual as well as combined exposures, indicating a common cellular response to combat the formed oxidative stresses. Biphasic response of AChE upon individual exposure confirmed their neurotoxic effects too. Expression profile of p53 (unaltered), Bax (lower or near-basal) and Bcl2 (comparatively higher), along with absence of DNA fragmentation indicated no induction of apoptosis in the co-exposed group. Tissue accumulation of arsenic and fluoride was significantly less in the brain of co-exposed zebrafish when compared to their individual exposures. This preliminary study indicates an antagonistic effect of these two toxicants in zebrafish brain and needs further studies involving oxidative stress independent markers to understand the detailed molecular mechanism.
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Affiliation(s)
- Paritosh Mondal
- Department of Zoology, Visva-Bharati, Santiniketan, 731235, West Bengal, India
| | - Pallab Shaw
- Department of Zoology, Visva-Bharati, Santiniketan, 731235, West Bengal, India
| | - Arpan Dey Bhowmik
- Department of Zoology, Visva-Bharati, Santiniketan, 731235, West Bengal, India
| | | | - Muthammal Sudarshan
- UGC-DAE Consortium for Scientific Research, Kolkata Centre, 3/LB-8, Bidhan Nagar, Kolkata, 700098, India
| | - Anindita Chakraborty
- UGC-DAE Consortium for Scientific Research, Kolkata Centre, 3/LB-8, Bidhan Nagar, Kolkata, 700098, India
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Krishnankutty N, Storgaard Jensen T, Kjær J, Jørgensen JS, Nielsen F, Grandjean P. Public-health risks from tea drinking: Fluoride exposure. Scand J Public Health 2021; 50:355-361. [PMID: 33557697 PMCID: PMC9096585 DOI: 10.1177/1403494821990284] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Aims: Due to new evidence on fluoride neurotoxicity during early life, this study
examined maternal exposure to fluoride through tea consumption in a
low-fluoride region and measured fluoride releases from commercially
available teas (tea bags and loose teas) to determine the need to limit
fluoride exposure. Methods: Maternal urine fluoride (MUF) concentrations were measured in spot urine
samples (N=118) from first-trimester pregnant women and in
prepared tea infusions made with deionised water from 33 brand teas and 57
loose-tea products, as determined by the direct method of using a
fluoride-selective electrode. Results: The fluoride concentration in the local drinking water supplies ranged from
0.10 to 0.18 mg/L, and the creatinine-adjusted MUF ranged from 0.09 to 1.57
mg/L. Seventeen per cent of the women were daily tea drinkers, and their
MUFs were higher than those with no consumption (p=0.002).
The fluoride concentration from tea bags ranged from 0.34 to 2.67 mg/L,
while loose teas showed 0.72–4.50 mg/L (black), 0.56–1.58 mg/L (oolong),
1.28–1.50 mg/L (green), and 0.33–1.17 mg/L (white tea). Conclusions: Fluoride exposure among pregnant women increases with tea consumption,
with likely risks of developmental neurotoxicity to their children. As
the fluoride release from tea varies widely, the fluoride concentration
should be indicated on tea packages in order to allow consumers to make
informed decisions on minimising their fluoride exposure.
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Affiliation(s)
| | | | - Jeannett Kjær
- Environmental Medicine, University of Southern Denmark, Denmark
| | | | | | - Philippe Grandjean
- Environmental Medicine, University of Southern Denmark, Denmark.,Department of Environmental Health, Harvard T.H. Chan School of Public Health, USA
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45
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Carwile JL, Ahrens KA, Seshasayee SM, Lanphear B, Fleisch AF. Predictors of Plasma Fluoride Concentrations in Children and Adolescents. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17249205. [PMID: 33317121 PMCID: PMC7764416 DOI: 10.3390/ijerph17249205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 12/03/2022]
Abstract
Despite increasing concerns about neurotoxicity of fluoride in children, sources of fluoride exposure apart from municipal water fluoridation are poorly understood. We aimed to describe the associations of demographics, drinking water characteristics, diet, and oral health behaviors with plasma fluoride concentrations in U.S. children. We used data from 3928 6–19-year-olds from the 2013–2016 National Health and Nutrition Examination Survey. We used a 24-h dietary recall to estimate recent consumption of fluoridated tap water and select foods. We estimated the associations of fluoridated tap water, time of last dental visit, use of toothpaste, and frequency of daily tooth brushing with plasma fluoride concentrations. The participants who consumed fluoridated (≥0.7 mg/L) tap water (n = 560, 16%) versus those who did not had 36% (95% CI: 22, 51) higher plasma fluoride. Children who drank black or green tea (n = 503, 13%) had 42% higher plasma fluoride concentrations (95% CI: 27, 58) than non-tea drinkers. The intake of other foods and oral health behaviors were not associated with plasma fluoride concentrations. The consumption of fluoridated tap water and tea substantially increases plasma fluoride concentrations in children. Quantifying the contribution of diet and other sources of fluoride is critical to establishing safe target levels for municipal water fluoridation.
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Affiliation(s)
- Jenny L. Carwile
- Center for Outcomes Research and Evaluation, Maine Medical Center Research Institute, Portland, ME 04101, USA; (S.M.S.); (A.F.F.)
- Correspondence:
| | - Katherine A. Ahrens
- Muskie School of Public Service, University of Southern Maine, Portland, ME 04101, USA;
| | - Shravanthi M. Seshasayee
- Center for Outcomes Research and Evaluation, Maine Medical Center Research Institute, Portland, ME 04101, USA; (S.M.S.); (A.F.F.)
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, Vancouver, BC V5A 1S6, Canada;
| | - Abby F. Fleisch
- Center for Outcomes Research and Evaluation, Maine Medical Center Research Institute, Portland, ME 04101, USA; (S.M.S.); (A.F.F.)
- Pediatric Endocrinology and Diabetes, Maine Medical Center, Portland, ME 04101, USA
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Lee N, Kang S, Lee W, Hwang SS. The Association between Community Water Fluoridation and Bone Diseases: A Natural Experiment in Cheongju, Korea. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17249170. [PMID: 33316869 PMCID: PMC7764285 DOI: 10.3390/ijerph17249170] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/04/2020] [Accepted: 12/05/2020] [Indexed: 11/16/2022]
Abstract
The present study aimed to investigate the association between bone diseases and community water fluoridation (CWF). An ecological study with a natural experiment design was conducted in Cheongju, South Korea, from 1 January 2004 to 31 December 2013. The community water fluoridation program was implemented in Cheongju and divided into CWF and non-CWF areas. To observe adverse health effects related to bone diseases, we conducted a spatio-temporal analysis of the prevalence of hip fracture, osteoporosis, and bone cancer in residents who have lived in CWF and non-CWF areas using National Health Insurance Service data. First, we used standardized incidence ratios to estimate the disease risk. Second, the hierarchical Bayesian Poisson spatio-temporal regression model was used to investigate the association between the selected bone diseases and CWF considering space and time interaction. The method for Bayesian estimation was based on the R-integrated nested Laplace approximation (INLA). Comparing the CWF area with the non-CWF area, there was no clear evidence that exposure to CWF increased health risks at the town level in Cheongju since CWF was terminated after 2004. The posterior relative risks (RR) of hip fracture was 0.95 (95% confidence intervals 0.87, 1.05) and osteoporosis was 0.94 (0.87, 1.02). The RR in bone cancer was a little high because the sample size very small compared to the other bone diseases (RR = 1.20 (0.89, 1.61)). The relative risk of selected bone diseases (hip fractures, osteoporosis, and bone cancer) increased over time but did not increase in the CWF area compared to non-CWF areas. CWF has been used to reduce dental caries in all population groups and is known for its cost-effectiveness. These findings suggest that CWF is not associated with adverse health risks related to bone diseases. This study provides scientific evidence based on a natural experiment design. It is necessary to continue research on the well-designed epidemiological studies and develop public health prevention programs to help in make suitable polices.
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Green R, Rubenstein J, Popoli R, Capulong R, Till C. Sex-specific neurotoxic effects of early-life exposure to fluoride: A review of the epidemiologic and animal literature. CURR EPIDEMIOL REP 2020; 7:263-273. [PMID: 33816056 PMCID: PMC8011433 DOI: 10.1007/s40471-020-00246-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW A growing body of evidence suggests adverse neurodevelopmental effects of early-life exposure to fluoride that may differ depending on timing of exposure and sex of the exposed. We conducted a literature search to identify the animal and human epidemiologic studies that examined sex-specific neurodevelopmental differences in response to prenatal and postnatal exposure to fluoride. RECENT FINDINGS Six of 138 animal studies and 15 of 106 human epidemiologic studies tested for sex-specific effects. Prenatal exposure to fluoride was associated with a male susceptibility to adverse behavioural effects in four of six animal studies and lower IQ in one of three prospective cohort studies. The body of evidence examining sex-effects associated with postnatal fluoride exposure was scarce, and many animal and cross-sectional human studies were considered to have a high risk of bias. SUMMARY Compared to females, male offspring appear to be more sensitive to prenatal, but not postnatal, exposure to fluoride. We discuss several sex-specific mechanisms and emphasize the need for future research.
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Affiliation(s)
- R. Green
- York University, Department of Psychology, 4700 Keele St
| | - J. Rubenstein
- York University, Department of Psychology, 4700 Keele St
| | - R. Popoli
- York University, Department of Psychology, 4700 Keele St
| | - R. Capulong
- York University, Department of Psychology, 4700 Keele St
| | - C. Till
- York University, Department of Psychology, 4700 Keele St
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48
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Xu K, An N, Huang H, Duan L, Ma J, Ding J, He T, Zhu J, Li Z, Cheng X, Zhou G, Ba Y. Fluoride exposure and intelligence in school-age children: evidence from different windows of exposure susceptibility. BMC Public Health 2020; 20:1657. [PMID: 33148225 PMCID: PMC7640398 DOI: 10.1186/s12889-020-09765-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 10/26/2020] [Indexed: 12/25/2022] Open
Abstract
Background The intellectual loss induced by fluoride exposure has been extensively studied, but the association between fluoride exposure in different susceptibility windows and children’s intelligence is rarely reported. Hence, we conducted a cross-sectional study to explore the association between fluoride exposure in prenatal and childhood periods and intelligence quotient (IQ). Methods We recruited 633 local children aged 7–13 years old randomly from four primary schools in Kaifeng, China in 2017. The children were divided into four groups, of which included: control group (CG, n = 228), only prenatal excessive fluoride exposure group (PFG, n = 107), only childhood excessive fluoride exposure group (CFG, n = 157), both prenatal and childhood excessive fluoride exposure group (BFG, n = 141). The concentrations of urinary fluoride (UF) and urinary creatinine (UCr) were determined by fluoride ion-selective electrode assay and a creatinine assay kit (picric acid method), respectively. The concentration of UCr-adjusted urinary fluoride (CUF) was calculated. IQ score was assessed using the second revision of the Combined Raven’s Test-The Rural in China (CRT-RC2). Threshold and saturation effects analysis, multiple linear regression analysis and logistic regression analysis were conducted to analyze the association between fluoride exposure and IQ. Results The mean IQ score in PFG was respectively lower than those in CG, CFG and BFG (P < 0.05). The odds of developing excellent intelligence among children in PFG decreased by 51.1% compared with children in CG (OR = 0.489, 95% CI: 0.279, 0.858). For all the children, CUF concentration of ≥1.7 mg/L was negatively associated with IQ scores (β = − 4.965, 95% CI: − 9.198, − 0.732, P = 0.022). In children without prenatal fluoride exposure, every 1.0 mg/L increment in the CUF concentration of ≥2.1 mg/L was related to a reduction of 11.4 points in children’s IQ scores (95% CI: − 19.2, − 3.5, P = 0.005). Conclusions Prenatal and childhood excessive fluoride exposures may impair the intelligence development of school children. Furthermore, children with prenatal fluoride exposure had lower IQ scores than children who were not prenatally exposed; therefore the reduction of IQ scores at higher levels of fluoride exposure in childhood does not become that evident.
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Affiliation(s)
- Kaihong Xu
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China.,Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Ning An
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Hui Huang
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China.,Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Leizhen Duan
- Department of Medical Services, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Jun Ma
- Department of Endemic Disease, Kaifeng Center for Disease Control and Prevention, Kaifeng, 475000, Henan, China
| | - Jizhe Ding
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Tongkun He
- The Medical Section, The Eighth People Hospital of Zhengzhou, Zhengzhou, 450000, Henan, China
| | - Jingyuan Zhu
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Zhiyuan Li
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Xuemin Cheng
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China.,Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Guoyu Zhou
- Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China. .,Yellow River Institute for Ecological Protection & Regional Coordinated Development, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| | - Yue Ba
- Department of Environmental Health, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China. .,Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, China. .,Yellow River Institute for Ecological Protection & Regional Coordinated Development, Zhengzhou University, Zhengzhou, 450001, Henan, China.
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Grandjean P, Hu H, Till C, Green R, Bashash M, Flora D, Tellez-Rojo MM, Song P, Lanphear B, Budtz-Jørgensen E. A Benchmark Dose Analysis for Maternal Pregnancy Urine-Fluoride and IQ in Children. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2020:2020.10.31.20221374. [PMID: 33173917 PMCID: PMC7654913 DOI: 10.1101/2020.10.31.20221374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
As a safe exposure level for fluoride in pregnancy has not been established, we used data from two prospective studies for benchmark dose modeling. We included mother-child pairs from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort in Mexico and the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort in Canada. Children were assessed for IQ at age 4 (n=211) and between 6 and 12 years (n=287) in the ELEMENT cohort and between ages 3 and 4 years (n=512) in the MIREC cohort. We calculated covariate-adjusted regression coefficients and their standard errors to explore the concentration-effect function for maternal urinary fluoride with children's IQ, including possible sex-dependence. Assuming a benchmark response of 1 IQ point, we derived benchmark concentrations (BMCs) of maternal urinary fluoride and benchmark concentration levels (BMCLs). No deviation from linearity was detected from the results of the two studies. Using a linear slope, the BMC for maternal urinary fluoride associated with a 1-point decrease in IQ scores of preschool-aged boys and girls was 0.29 mg/L (BMCL, 0.18 mg/L). The BMC was 0.30 mg/L (BMCL, 0.19 mg/L) when pooling the IQ scores from the older ELEMENT children and the MIREC cohort. Boys showed slightly lower BMC values compared with girls. Relying on two prospective studies, maternal urine-fluoride exposure at levels commonly occurring in the general population, the joint data showed BMCL results about 0.2 mg/L. These results can be used to guide decisions on preventing excess fluoride exposure in vulnerable populations.
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Affiliation(s)
- Philippe Grandjean
- Harvard T.H. Chan School of Public Health, Department of Environmental Health, Boston, MA 02115, USA
- Department of Public Health, University of Southern Denmark, Odense, Denmark
| | - Howard Hu
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - Rivka Green
- Faculty of Health, York University, Ontario, Canada
| | - Morteza Bashash
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - David Flora
- Faculty of Health, York University, Ontario, Canada
| | - Martha Maria Tellez-Rojo
- Centro de Investigacion en Salud Poblacional, Instituto Nacional de Salud Publica, Cuernavaca, Morelos, Mexico
| | - Peter Song
- Department of Biostatistics, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, British Columbia, Canada
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50
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Mechanisms of Fluoride Toxicity: From Enzymes to Underlying Integrative Networks. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10207100] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Fluoride has been employed in laboratory investigations since the early 20th century. These studies opened the understanding of fluoride interventions to fundamental biological processes. Millions of people living in endemic fluorosis areas suffer from various pathological disturbances. The practice of community water fluoridation used prophylactically against dental caries increased concern of adverse fluoride effects. We assessed the publications on fluoride toxicity until June 2020. We present evidence that fluoride is an enzymatic poison, inducing oxidative stress, hormonal disruptions, and neurotoxicity. Fluoride in synergy with aluminum acts as a false signal in G protein cascades of hormonal and neuronal regulations in much lower concentrations than fluoride acting alone. Our review shows the impact of fluoride on human health. We suggest focusing the research on fluoride toxicity to the underlying integrative networks. Ignorance of the pluripotent toxic effects of fluoride might contribute to unexpected epidemics in the future.
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