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Liu X, Lau CLB, Ding H, Matinlinna JP, Tsoi JKH. Enamel Remineralisation with a Novel Sodium Fluoride-Infused Bristle Toothbrush. Dent J (Basel) 2024; 12:142. [PMID: 38786540 PMCID: PMC11119043 DOI: 10.3390/dj12050142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/29/2024] [Accepted: 05/08/2024] [Indexed: 05/25/2024] Open
Abstract
This study aims to investigate whether toothbrushes with fluoride-infused bristles have any (re)mineralisation effects on bovine enamel. Bovine incisors (N = 160) were extracted, and the buccal side of the crown was cut into dimensions of ~5 mm × 5 mm with a low-speed saw. These specimens were randomly allocated into four groups: half (80 teeth) were stored in demineralising solution (DM), and the other half were stored in deionised water (DW) for 96 h. Then, they were brushed with a force of 2.0 ± 0.1 N for five min with a manual toothbrush with either fluoride-infused (TF) or regular (TR) bristles. Microhardness (Vickers), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were used to investigate the surfaces of the bovine enamel specimens before and after brushing. Two-way ANOVA was used to analyse the hardness data, and the pairwise comparison method was used to analyse the Ca/P ratio, for each group at α = 0.05. The results show that brushing with either of these toothbrushes increased the Vickers microhardness on DM and DW enamel (p < 0.001), whereas hydroxyapatite was revealed in all groups by XRD. The DM samples showed a significant increase (p < 0.05) in the Ca/P ratios after brushing with TR and TF. Conversely, under DW conditions, these ratios decreased significantly after brushing. In terms of the F atomic%, TF increased significantly. SEM revealed mineral deposition in the DM groups after toothbrushing. To conclude, toothbrushing effectively induces the microhardness of sound and demineralised enamel, while fluoride-infused bristles might be able to retain fluoride on the enamel surface.
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Affiliation(s)
- Xiaotian Liu
- Department of Orthodontics, Tianjin Stomatological Hospital, School of Medicine, Nankai University, Tianjin 300041, China
- Dental Materials Science, Applied and Oral Science and Community Oral Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (H.D.); (J.P.M.)
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, Tianjin 300041, China
| | - Chun Lok Bryan Lau
- Dental Materials Science, Applied and Oral Science and Community Oral Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (H.D.); (J.P.M.)
| | - Hao Ding
- Dental Materials Science, Applied and Oral Science and Community Oral Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (H.D.); (J.P.M.)
| | - Jukka Pekka Matinlinna
- Dental Materials Science, Applied and Oral Science and Community Oral Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (H.D.); (J.P.M.)
- Division of Dentistry, School of Medical Sciences, University of Manchester, Manchester M13 9PL, UK
| | - James K. H. Tsoi
- Dental Materials Science, Applied and Oral Science and Community Oral Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China (H.D.); (J.P.M.)
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Hall M, Hornung R, Chevrier J, Ayotte P, Lanphear B, Till C. Fluoride exposure and thyroid hormone levels in pregnancy: The MIREC cohort. ENVIRONMENT INTERNATIONAL 2024; 184:108442. [PMID: 38237505 PMCID: PMC10973885 DOI: 10.1016/j.envint.2024.108442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 01/03/2024] [Accepted: 01/10/2024] [Indexed: 02/23/2024]
Abstract
BACKGROUND Fluoride exposure may increase the risk of hypothyroidism, but results from previous studies are inconsistent at low-level fluoride exposure (i.e., ≤0.7 mg/L). Human studies of fluoride and thyroid hormone levels in pregnancy are scarce. OBJECTIVES We examined associations between fluoride exposure and maternal thyroid hormone levels in a Canadian pregnancy cohort, with consideration for fetal sex-specific effects. METHODS We measured fluoride concentrations in drinking water and spot urine samples collected during each trimester from 1876 pregnant women enrolled in the Maternal-Infant Research on Environmental Chemicals (MIREC) study. We also measured maternal thyroid stimulating hormone (TSH), free thyroxine (FT4), and total thyroxine (TT4) levels during the first trimester of pregnancy. We used linear and non-linear regression models to estimate associations between fluoride exposure and levels of TSH, FT4, and TT4. We explored effect modification by fetal sex and considered maternal iodine status as a potential confounder. RESULTS A 1 mg/L increase in urinary fluoride was associated with a 0.30 (95 %CI: 0.08, 0.51) logarithmic unit (i.e., 35.0 %) increase in TSH among women pregnant with females, but not males (B = 0.02; 95 %CI: -0.16, 0.19). Relative to women with urinary fluoride concentrations in the first quartile (0.05-0.32 mg/L), those with levels in the third quartile (0.49-0.75 mg/L) had higher FT4 and TT4 (i.e., inverted J-shaped associations), but the association was not statistically significant after adjustment for covariates (p = 0.06). Water fluoride concentration showed a U-shaped association with maternal FT4, whereby women with water fluoride concentrations in the second (0.13-0.52 mg/L) and third (0.52-0.62 mg/L) quartiles had significantly lower FT4 compared to those with levels in the first quartile (0.04-0.13 mg/L). Adjustment for maternal iodine status did not change the results. DISCUSSION Fluoride exposure was associated with alterations in maternal thyroid hormone levels, the magnitude of which appeared to vary by fetal sex. Given the importance of maternal thyroid hormones for fetal neurodevelopment, replication of findings is warranted.
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Affiliation(s)
- Meaghan Hall
- Psychology Department, York University, Toronto, ON, Canada.
| | - Rick Hornung
- Retired, Consultant to Psychology Department, York University, Toronto, ON, Canada.
| | - Jonathan Chevrier
- School of Population and Global Health, McGill University, Montreal, QC, Canada.
| | - Pierre Ayotte
- Department of Social and Preventive Medicine, Faculty of Medicine, Université Laval, Québec City, QC, Canada.
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada.
| | - Christine Till
- Psychology Department, York University, Toronto, ON, Canada.
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Iamandii I, De Pasquale L, Giannone ME, Veneri F, Generali L, Consolo U, Birnbaum LS, Castenmiller J, Halldorsson TI, Filippini T, Vinceti M. Does fluoride exposure affect thyroid function? A systematic review and dose-response meta-analysis. ENVIRONMENTAL RESEARCH 2024; 242:117759. [PMID: 38029816 DOI: 10.1016/j.envres.2023.117759] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/01/2023]
Abstract
INTRODUCTION Fluoride exposure may have various adverse health effects, including affecting thyroid function and disease risk, but the pattern of such relation is still uncertain. METHODS We systematically searched human studies assessing the relation between fluoride exposure and thyroid function and disease. We compared the highest versus the lowest fluoride category across these studies, and we performed a one-stage dose-response meta-analysis for aggregated data to explore the shape of the association. RESULTS Most retrieved studies (27 of which with a cross-sectional design) were conducted in Asia and in children, assessing fluoride exposure through its concentrations in drinking water, urine, serum, or dietary intake. Twenty-four studies reported data on thyroid function by measuring thyroid-related hormones in blood (mainly thyroid-stimulating-hormone - TSH), 9 reported data on thyroid disease, and 4 on thyroid volume. By comparing the highest versus the lowest fluoride categories, overall mean TSH difference was 1.05 μIU/mL. Dose-response curve showed no change in TSH concentrations in the lowest water fluoride exposure range, while the hormone levels started to linearly increase around 2.5 mg/L, also dependending on the risk of bias of the included studies. The association between biomarkers of fluoride exposure and TSH was also positive, with little evidence of a threshold. Evidence for an association between fluoride exposure and blood concentrations of thyroid hormones was less evident, though there was an indication of inverse association with triiodothyronine. For thyroid disease, the few available studies suggested a positive association with goiter and with hypothyroidism in both children and adults. CONCLUSIONS Overall, exposure to high-fluoride drinking water appears to non-linearly affect thyroid function and increase TSH release in children, starting above a threshold of exposure, and to increase the risk of some thyroid diseases.
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Affiliation(s)
- Inga Iamandii
- 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, Modena, Italy
| | - Lisa De Pasquale
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Maria Edvige Giannone
- 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, Modena, Italy
| | - 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
| | - 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
| | - 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
| | - Linda S Birnbaum
- Nicholas School of the Environment, Duke University, Durham, NC, USA
| | - Jacqueline Castenmiller
- Office for Risk Assessment & Research, Netherlands Food and Consumer Product Safety Authority, Utrecht, the Netherlands
| | - Thorhallur I Halldorsson
- Department of Epidemiology Research, Centre for Fetal Programming, Copenhagen, Denmark; Faculty of Food Science and Nutrition, University of Iceland, Reykjavík, Iceland
| | - 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, Modena, Italy; School of Public Health, University of California Berkeley, Berkeley, CA, USA
| | - 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, Modena, Italy; Department of Epidemiology, Boston University School of Public Health, Boston, MA, USA.
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Muthu Prabhu S, Yusuf M, Ahn Y, Park HB, Choi J, Amin MA, Yadav KK, Jeon BH. Fluoride occurrence in environment, regulations, and remediation methods for soil: A comprehensive review. CHEMOSPHERE 2023; 324:138334. [PMID: 36893864 DOI: 10.1016/j.chemosphere.2023.138334] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/04/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Fluoride, a naturally occurring chemical element, is largely insoluble in soils. More than 90% of the fluoride in soil is bound to soil particles and is unable to be dissolved. As part of the soil, fluoride is predominantly located in the colloid or clay fraction of the soil, and the movement of fluoride is strongly affected by the sorption capacity of the soil, which is affected by pH, the type of soil sorbent present, and the salinity. The Canadian Council of Ministers of the Environment soil quality guideline for fluoride in soils under a residential/parkland land use scenario is 400 mg/kg. In this review, we focus on fluoride contamination in soil and subsurface environments, and the various sources of fluorides are discussed in detail. The average fluoride concentration in soil in different countries and their regulations for soil and water are comprehensively reviewed. In this article, the latest advances in defluoridation methods are highlighted and the importance of further research addressing efficient and cost-effective methods to remediate fluoride contamination in soil is critically discussed. Methods used to mitigate fluoride risks by removing fluoride from the soil are presented. We strongly recommend that regulators and soil chemists in all countries explore opportunities to improve defluoridation methods and consider adopting more stringent regulations for fluoride in soil depending on geologic conditions.
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Affiliation(s)
- Subbaiah Muthu Prabhu
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, Republic of Korea; Department of Chemistry, School of Advanced Sciences, VIT-AP University, Vijayawada, 522 237, Andhra Pradesh, India
| | - Mohammed Yusuf
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Yongtae Ahn
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
| | - Ho Bum Park
- Department of Energy Engineering, Hanyang University, Seoul, 04763, Republic of Korea
| | - Jaeyoung Choi
- Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology, Hwarang-ro 14, Seongbuk-gu, Seoul, 02792, Republic of Korea
| | - Mohammed A Amin
- Department of Chemistry, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia
| | - Krishna Kumar Yadav
- Faculty of Science and Technology, Madhyanchal Professional University, Tatibad, Bhopal, 462044, India
| | - Byong-Hun Jeon
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul, 04763, Republic of Korea.
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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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Hall M, Lanphear B, Chevrier J, Hornung R, Green R, Goodman C, Ayotte P, Martinez-Mier EA, Zoeller RT, Till C. Fluoride exposure and hypothyroidism in a Canadian pregnancy cohort. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 869:161149. [PMID: 36764861 PMCID: PMC9992168 DOI: 10.1016/j.scitotenv.2022.161149] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/19/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
BACKGROUND While fluoride can have thyroid-disrupting effects, associations between low-level fluoride exposure and thyroid conditions remain unclear, especially during pregnancy when insufficient thyroid hormones can adversely impact offspring development. OBJECTIVES We evaluated associations between fluoride exposure and hypothyroidism in a Canadian pregnancy cohort. METHODS We measured fluoride concentrations in drinking water and three dilution-corrected urine samples and estimated fluoride intake based on self-reported beverage consumption. We classified women enrolled in the Maternal-Infant Research on Environmental Chemicals Study as euthyroid (n = 1301), subclinical hypothyroid (n = 100) or primary hypothyroid (n = 107) based on their thyroid hormone levels in trimester one. We used multinomial logistic regression to estimate the association between fluoride exposure and classification of either subclinical or primary hypothyroidism and considered maternal thyroid peroxidase antibody (TPOAb) status, a marker of autoimmune hypothyroidism, as an effect modifier. In a subsample of 466 mother-child pairs, we used linear regression to explore the association between maternal hypothyroidism and child Full-Scale IQ (FSIQ) at ages 3-to-4 years and tested for effect modification by child sex. RESULTS A 0.5 mg/L increase in drinking water fluoride concentration was associated with a 1.65 (95 % confidence interval [CI]: 1.04, 2.60) increased odds of primary hypothyroidism. In contrast, we did not find a significant association between urinary fluoride (adjusted odds ratio [aOR]: 1.00; 95%CI: 0.73, 1.39) or fluoride intake (aOR: 1.25; 95%CI: 0.99, 1.57) and hypothyroidism. Among women with normal TPOAb levels, the risk of primary hypothyroidism increased with both increasing water fluoride and fluoride intake (aOR water fluoride concentration: 2.85; 95%CI: 1.25, 6.50; aOR fluoride intake: 1.75; 95%CI: 1.27, 2.41). Children born to women with primary hypothyroidism had lower FSIQ scores compared to children of euthyroid women, especially among boys (B coefficient: -8.42; 95 % CI: -15.33, -1.50). DISCUSSION Fluoride in drinking water was associated with increased risk of hypothyroidism in pregnant women. Thyroid disruption may contribute to developmental neurotoxicity of fluoride.
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Affiliation(s)
- Meaghan Hall
- Psychology Department, York University, Toronto, ON, Canada
| | - Bruce Lanphear
- Faculty of Health Sciences, Simon Fraser University, Burnaby, BC, Canada
| | - Jonathan Chevrier
- School of Population and Global Health, McGill University, Montreal, QC, Canada
| | - Rick Hornung
- Retired; Consultant to Psychology Department, York University, Toronto, ON, Canada
| | - Rivka Green
- Psychology Department, York University, Toronto, ON, Canada
| | - Carly Goodman
- Psychology Department, York University, Toronto, ON, Canada
| | - Pierre Ayotte
- Department of Social and Preventive Medicine, Faculty of Medicine, Université Laval, Québec City, QC, Canada
| | | | - R Thomas Zoeller
- Biology Department, The University of Massachusetts Amherst, Amherst, MA, United States
| | - Christine Till
- Psychology Department, York University, Toronto, ON, Canada.
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Zhou J, Sun D, Wei W. Necessity to Pay Attention to the Effects of Low Fluoride on Human Health: an Overview of Skeletal and Non-skeletal Damages in Epidemiologic Investigations and Laboratory Studies. Biol Trace Elem Res 2023; 201:1627-1638. [PMID: 35661326 DOI: 10.1007/s12011-022-03302-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 05/26/2022] [Indexed: 12/15/2022]
Abstract
Due to the implementation of water improvement and fluoride reduction plans supported by central and local governments in recent years, areas with high fluoride exposure are being gradually decreased. Therefore, it is of practical importance to study the effect of low fluoride on human health. Epidemiologic investigations and in vivo and in vitro studies based on low fluoride have also confirmed that fluoride not only causes skeletal damage, such as dental fluorosis, but also causes non-skeletal damage involving the cardiovascular system, nervous system, hepatic and renal function, reproductive system, thyroid function, blood glucose homeostasis, and the immune system. This article summarizes the effects of low fluoride on human and animal skeletal and non-skeletal systems. A preliminary exploration of corresponding mechanisms that will help to fully understand the harm of low fluoride on human health was undertaken to provide the basis for establishing new water fluoride standards and help to implement individual guidance.
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Affiliation(s)
- Jing Zhou
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, Heilongjiang Province, China
- National Health Commission, Key Laboratory of Etiology and Epidemiology, Harbin Medical University (23618504), Harbin, 150081, Heilongjiang Province, China
- Heilongjiang Provincial Key Laboratory of Trace Elements and Human Health, Harbin Medical University, 150081, Harbin, Heilongjiang Province, China
| | - Dianjun Sun
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, Heilongjiang Province, China
- National Health Commission, Key Laboratory of Etiology and Epidemiology, Harbin Medical University (23618504), Harbin, 150081, Heilongjiang Province, China
- Heilongjiang Provincial Key Laboratory of Trace Elements and Human Health, Harbin Medical University, 150081, Harbin, Heilongjiang Province, China
| | - Wei Wei
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, 150081, Heilongjiang Province, China.
- National Health Commission, Key Laboratory of Etiology and Epidemiology, Harbin Medical University (23618504), Harbin, 150081, Heilongjiang Province, China.
- Heilongjiang Provincial Key Laboratory of Trace Elements and Human Health, Harbin Medical University, 150081, Harbin, Heilongjiang Province, China.
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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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Abstract
BACKGROUND Increasingly, patients are asking their physicians about the benefits of dietary and alternative approaches to manage their diseases, including thyroid disease. We seek to review the evidence behind several of the vitamins, minerals, complementary medicines, and elimination diets that patients are most commonly using for the treatment of thyroid disorders. SUMMARY Several trace elements are essential to normal thyroid function, and their supplementation has been studied in various capacities. Iodine supplementation has been implemented on national scales through universal salt iodization with great success in preventing severe thyroid disease, but can conversely cause thyroid disorders when given in excess. Selenium and zinc supplementation has been found to be beneficial in specific populations with otherwise limited generalizability. Other minerals, such as vitamin B12, low-dose naltrexone, and ashwagandha root extract, have little to no evidence of any impact on thyroid disorders. Avoidance of gluten and dairy has positive impacts only in patients with concomitant sensitivities to those substances, likely by improving absorption of levothyroxine. Avoidance of cruciferous vegetables and soy has little proven benefit in patients with thyroid disorders. CONCLUSION While many patients are seeking to avoid conventional therapy and instead turn to alternative and dietary approaches to thyroid disease management, many of the most popular approaches have no proven benefit or have not been well studied. It is our responsibility to educate our patients about the evidence for or against benefit, potential harms, or dearth of knowledge behind these strategies.
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Affiliation(s)
- Dana Larsen
- Division of Endocrinology, Diabetes and Bone Disease, Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Sargun Singh
- Government Medical College Amritsar, Amritsar, Punjab, India
| | - Maria Brito
- Division of Endocrinology, Diabetes and Bone Disease, Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
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10
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Kampouri M, Gustin K, Stråvik M, Barman M, Levi M, Daraki V, Jacobsson B, Sandin A, Sandberg AS, Wold AE, Vahter M, Kippler M. Association of maternal urinary fluoride concentrations during pregnancy with size at birth and the potential mediation effect by maternal thyroid hormones: The Swedish NICE birth cohort. ENVIRONMENTAL RESEARCH 2022; 214:114129. [PMID: 35998692 DOI: 10.1016/j.envres.2022.114129] [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: 05/06/2022] [Revised: 07/26/2022] [Accepted: 08/14/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Observational studies have indicated that elevated maternal fluoride exposure during pregnancy may impair child neurodevelopment but a potential impact on birth outcomes is understudied. OBJECTIVES To evaluate the impact of gestational fluoride exposure on birth outcomes (birth size and gestational age at birth) and to assess the potential mediating role of maternal thyroid hormones. METHODS We studied 583 mother-child dyads in the NICE cohort in northern Sweden. Maternal fluoride exposure was assessed by measuring urinary concentrations at late pregnancy (median: 29th gestational week) using an ion selective electrode. Plasma levels of free and total thyroxine (fT4, tT4) and triiodothyronine (fT3, tT3), and thyroid stimulating hormone (TSH) were measured with electrochemiluminescence immunoassays. The infant's weight, length, head circumference, and gestational age at birth were extracted from hospital records. RESULTS Median urinary fluoride concentration was 0.71 mg/L (5th-95th percentile 0.31-1.9 mg/L; specific gravity adjusted). In multivariable-adjusted regression models, every 1 mg/L increase of maternal urinary fluoride was associated with a mean increase in birth weight by 84 g (95%CI: 30, 138), length by 0.41 cm (95%CI: 0.18, 0.65), head circumference by 0.3 cm (95%CI: 0.1, 0.4), and with increased odds of being born large for gestational age (OR = 1.39, 95%CI: 1.03, 1.89). Every 1 mg/L increase of maternal urinary fluoride was also associated with a mean increase of the plasma fT3:fT4 ratio (B = 0.007, 95%CI: 0.000, 0.014), but not with the hormones or TSH. In mediation analyses, the maternal fT3:fT4 ratio did not explain the urinary fluoride-birth size relationships. DISCUSSION Gestational urinary fluoride concentrations were associated with increased size at birth and even with increased odds of being born large for gestational age. The fluoride-related associations with increased size at birth were not explained by changes in maternal thyroid hormone levels.
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Affiliation(s)
- Mariza Kampouri
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Klara Gustin
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Mia Stråvik
- Food and Nutrition Science, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Malin Barman
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden; Food and Nutrition Science, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Michael Levi
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Vasiliki Daraki
- Department of Endocrinology, University Hospital of Heraklion, Heraklion, Greece
| | - Bo Jacobsson
- Department of Obstetrics and Gynecology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden; Institute of Clinical Sciences, Department of Obstetrics and Gynecology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Anna Sandin
- Department of Clinical Science, Pediatrics, Sunderby Research Unit, Umeå University, Sweden
| | - Ann-Sofie Sandberg
- Food and Nutrition Science, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Agnes E Wold
- Institute of Biomedicine, Department of Infectious Diseases, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Marie Vahter
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Maria Kippler
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
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11
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Masoud MHZ, Rajmohan N, Basahi JM, Niyazi BAM. Application of water quality indices and health risk models in the arid coastal aquifer, Southern Saudi Arabia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:70493-70507. [PMID: 35585455 DOI: 10.1007/s11356-022-20835-5] [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: 11/02/2021] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
A systematic study was performed in the arid coastal aquifer to evaluate groundwater quality using drinking water quality indices (DWQI) and health risk assessment models in southern Saudi Arabia. Groundwater samples were collected (n = 80) and analysed for major and minor ions. Results suggest that 85% of wells are unsuitable for drinking due to high salinity and hardness. Likewise, high NO3- and F- are encountered in 51% and 46% of wells, respectively. High salinity, Cl- and SO42- are noticed in the coastal wells, which are derived from saline sources, evaporation and anthropogenic activities. High NO3- is originated from anthropogenic sources and the nitrification process. Recharge of wastewater with high NO3- is mixed with high salinity groundwater in this shallow aquifer. DWQI indicates that 66% of samples are poor to unsuitable classes. Wells with poor quality groundwater existed in the coastal belt and water quality is degraded while moving from upstream to downstream. The average values of hazard quotient (HQoral, NO3-, F-) and total hazard index (THI) ensured that highly vulnerable groups are in the order of infants > children > adults. In the study region, the THI are > 1 in 75% (adults), 89% (children) and 94% (infants) of samples, respectively. The spatial distribution of HQoral reveals that groundwater in the coastal and southern regions is not advisable for direct oral ingestion, which causes serious non-carcinogenic health risk to inhabitants. Groundwater in these regions needs proper treatment to remove the contaminants before use.
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Affiliation(s)
- Milad H Z Masoud
- Water Research Center, King Abdulaziz University, P.O. Box 80200, Jeddah, 21598, Saudi Arabia.
- Hydrology Department, Desert Research Centre, Cairo, Egypt.
| | - Natarajan Rajmohan
- Water Research Center, King Abdulaziz University, P.O. Box 80200, Jeddah, 21598, Saudi Arabia
| | - Jalal M Basahi
- Department of Hydrology, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, P.O. Box 80200, Jeddah, 21598, Saudi Arabia
| | - Burhan A M Niyazi
- Water Research Center, King Abdulaziz University, P.O. Box 80200, Jeddah, 21598, Saudi Arabia
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12
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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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13
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Ibarluzea J, Gallastegi M, Santa-Marina L, Jiménez Zabala A, Arranz E, Molinuevo A, Lopez-Espinosa MJ, Ballester F, Villanueva CM, Riano I, Sunyer J, Tardon A, Lertxundi A. Prenatal exposure to fluoride and neuropsychological development in early childhood: 1-to 4 years old children. ENVIRONMENTAL RESEARCH 2022; 207:112181. [PMID: 34627799 DOI: 10.1016/j.envres.2021.112181] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 09/21/2021] [Accepted: 10/03/2021] [Indexed: 05/28/2023]
Abstract
BACKGROUND Cross-sectional and prospective studies have provided evidence of the neurotoxic effect of early exposure to fluoride (F) in pregnancy. It has been negatively associated with cognitive development during childhood, with most research conducted in areas with high F levels in community drinking water (CDW). METHOD Data from 316 to 248 mother-child pairs from the Infancia y Medio Ambiente (Childhood and Environment, INMA) birth cohort project with maternal urinary F level adjusted for creatinine (MUFcr) measurements in the first and third trimesters of pregnancy. Children's cognitive domains and intelligence indexes were evaluated using the Bayley Scales (age of 1) and the McCarthy Scales (age of 4). Multiple linear regression analyses were carried out adjusting for a wide range of covariates related to the child, mother, family context and other potential neurotoxicants. RESULTS No association was found between MUFcr levels and Bayley Mental Development Index score. Nevertheless, regarding the McCarthy scales, it was found that per unit (mg/g) of MUFcr across the whole pregnancy, scores in boys were greater for the verbal, performance, numeric and memory domains (β = 13.86, CI 95%: 3.91, 23.82), (β = 5.86, CI 95%: 0.32, 11.39), (β = 6.22, CI 95%: 0.65, 11.79) and (β = 11.63, CI 95%: 2.62, 20.63) respectively and for General Cognitive Index (β = 15.4, CI 95%: 6.32, 24.48). For girls there was not any cognitive score significantly associated with MUFcr, being the sex-F interactions significant (P interaction <0.05). Including other toxicants levels, quality of family context or deprivation index did not substantially change the results. CONCLUSIONS In boys, positive associations were observed between MUFcr and scores in cognitive domains at the age of 4. These findings are inconsistent with those from some previous studies and indicate the need for other population-based studies to confirm or overturn these results at low levels of F in CDW.
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Affiliation(s)
- Jesús Ibarluzea
- Ministry of Health of the Basque Government, Sub-Directorate for Public Health and Addictions of Gipuzkoa, 20013, San Sebastián, Spain; Faculty of Psychology of the University of the Basque Country, 20018, San Sebastian, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Biodonostia Health Research Institute, Environmental Epidemiology and Child Development Group, 20014, San Sebastian, Spain
| | - Mara Gallastegi
- Biodonostia Health Research Institute, Environmental Epidemiology and Child Development Group, 20014, San Sebastian, Spain.
| | - Loreto Santa-Marina
- Ministry of Health of the Basque Government, Sub-Directorate for Public Health and Addictions of Gipuzkoa, 20013, San Sebastián, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Biodonostia Health Research Institute, Environmental Epidemiology and Child Development Group, 20014, San Sebastian, Spain
| | - Ana Jiménez Zabala
- Ministry of Health of the Basque Government, Sub-Directorate for Public Health and Addictions of Gipuzkoa, 20013, San Sebastián, Spain; Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Biodonostia Health Research Institute, Environmental Epidemiology and Child Development Group, 20014, San Sebastian, Spain
| | - Enrique Arranz
- Faculty of Psychology of the University of the Basque Country, 20018, San Sebastian, Spain; Biodonostia Health Research Institute, Environmental Epidemiology and Child Development Group, 20014, San Sebastian, Spain
| | - Amaia Molinuevo
- Biodonostia Health Research Institute, Environmental Epidemiology and Child Development Group, 20014, San Sebastian, Spain
| | - Maria-Jose Lopez-Espinosa
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Nursing School, Universitat de València, 46010, Valencia, Spain; Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, 46020, Valencia, Spain
| | - Ferran Ballester
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Nursing School, Universitat de València, 46010, Valencia, Spain; Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, 46020, Valencia, Spain
| | - Cristina M Villanueva
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Barcelona Institute for Global Health (ISGlobal), 08003, Barcelona, Spain; Municipal Institute of Medical Research, IMIM-Hospital del Mar, 08003, Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08002, Barcelona, Spain
| | - Isolina Riano
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33001, Oviedo, Asturias, Spain; Servicio de Pediatría, Endocrinología, HUCA, Roma Avenue, 33001, Oviedo, Asturias, Spain
| | - Jordi Sunyer
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Epidemiology and Environmental Health Joint Research Unit, FISABIO-Universitat Jaume I-Universitat de València, 46020, Valencia, Spain; Barcelona Institute for Global Health (ISGlobal), 08003, Barcelona, Spain; Municipal Institute of Medical Research, IMIM-Hospital del Mar, 08003, Barcelona, Spain
| | - Adonina Tardon
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), 33001, Oviedo, Asturias, Spain; Unit of Molecular Cancer Epidemiology, University Institute of Oncology of the Principality of Asturias (IUOPA), Department of Medicine, University of Oviedo, Julian Clavería Street, 33006, Oviedo, Asturias, Spain
| | - Aitana Lertxundi
- Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), 28029, Madrid, Spain; Biodonostia Health Research Institute, Environmental Epidemiology and Child Development Group, 20014, San Sebastian, Spain; Department of Preventive Medicine and Public Health, Faculty of Medicine, University of the Basque Country (UPV/EHU), 48940, Leioa, Spain
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14
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Du Y, Zhou G, Gong B, Ma J, An N, Gao M, Yang M, Ma Q, Huang H, Zuo Q, Ba Y. Iodine Modifies the Susceptibility of Thyroid to Fluoride Exposure in School-age Children: a Cross-sectional Study in Yellow River Basin, Henan, China. Biol Trace Elem Res 2021; 199:3658-3666. [PMID: 33479887 DOI: 10.1007/s12011-020-02519-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 11/25/2020] [Indexed: 02/02/2023]
Abstract
Excessive fluoride exposure has detrimental effects on the thyroid gland, which may be modified by iodine. However, the role of iodine in it remains unclear. This study aims to evaluate the role of iodine in thyroid abnormalities caused by fluoride exposure in school-age children. A total of 446 children aged 7-12 years were recruited from Tongxu County, Henan province, in 2017 (ZZUIRB 2017-018). We obtained demographic information through questionnaire surveys. The concentrations of urinary fluoride (UF) and urinary iodine (UI) were determined by the ion-selective electrode method and the catalytic spectrophotometric method, respectively. The radiation immunoassay was used to determine the serum concentrations of total triiodothyronine (TT3), total thyroxine (TT4), and thyroid-stimulating hormone (TSH). The B-mode ultrasound was performed to assess thyroid volumes (Tvols). The associations between fluoride exposure and thyroid-related indicators were tested by linear regression models. We found that Tvols increased by 0.22 (95% CI: 0.14, 0.31) cm3 with each standard deviation increment of UF. Moreover, Tvols in boys were more susceptible to fluoride exposure than those in girls, and the Tvols of children with high urinary iodine are less susceptible to fluoride exposure (P for interaction < 0.05). We also observed that TT3 levels were negatively related to UF concentrations at moderate urinary iodine levels (≤ 300 μg/l). Fluoride exposure can elevate the Tvols of school-age children, especially in boys, and high levels of iodine may alleviate this effect to some extent.
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Affiliation(s)
- Yuhui Du
- Department of Environmental Health & Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China
| | - Guoyu Zhou
- Department of Environmental Health & Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China
- Yellow River Institute for Ecological Protection & Regional Coordinated Development, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Biao Gong
- Department of Endemic Disease, Kaifeng Center for Disease Control and Prevention, Kaifeng, 475000, Henan, People's Republic of China
| | - Jun Ma
- Department of Endemic Disease, Kaifeng Center for Disease Control and Prevention, Kaifeng, 475000, Henan, People's Republic of China
| | - Ning An
- Department of Environmental Health & Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China
| | - Minghui Gao
- Department of Environmental Health & Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China
| | - Meng Yang
- Department of Environmental Health & Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China
| | - Qiang Ma
- Teaching and Research Office, the Third Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, Henan, People's Republic of China
| | - Hui Huang
- Department of Environmental Health & Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China
| | - Qiting Zuo
- Yellow River Institute for Ecological Protection & Regional Coordinated Development, Zhengzhou University, Zhengzhou, 450001, People's Republic of China
| | - Yue Ba
- Department of Environmental Health & Environment and Health Innovation Team, School of Public Health, Zhengzhou University, Zhengzhou, 450001, Henan, People's Republic of China.
- Yellow River Institute for Ecological Protection & Regional Coordinated Development, Zhengzhou University, Zhengzhou, 450001, People's Republic of China.
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15
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Selected Essential and Toxic Chemical Elements in Hypothyroidism-A Literature Review (2001-2021). Int J Mol Sci 2021; 22:ijms221810147. [PMID: 34576309 PMCID: PMC8472829 DOI: 10.3390/ijms221810147] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 09/13/2021] [Accepted: 09/16/2021] [Indexed: 02/06/2023] Open
Abstract
Thyroid hormones are known for controlling metabolism of lipids, carbohydrates, proteins, minerals, and electrolytes and for regulating body temperature. Normal thyroid status depends on the chemical/elemental composition of body fluids and tissues, which changes depending on physiological state, lifestyle and environment. A deficiency or excess of certain essential chemical elements (selenium, zinc, copper, iron or fluorine) or exposure to toxic (cadmium or lead) or potentially toxic elements (manganese or chromium) interacts with thyroid hormone synthesis and may disturb thyroid homeostasis. In our review, accessible databases (Scopus, PubMed and Web of Science) were searched for articles from 2001-2021 on the influence of selected chemical elements on the development of hypothyroidism. Our review adopted some of the strengths of a systematic review. After non-eligible reports were rejected, 29 remaining articles were reviewed. The review found that disruption of the physiological levels of elements in the body adversely affects the functioning of cells and tissues, which can lead to the development of disease.
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16
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Revelo-Mejía IA, Hardisson A, Rubio C, Gutiérrez ÁJ, Paz S. Dental Fluorosis: the Risk of Misdiagnosis-a Review. Biol Trace Elem Res 2021; 199:1762-1770. [PMID: 32705431 DOI: 10.1007/s12011-020-02296-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/19/2020] [Indexed: 11/25/2022]
Abstract
Fluoride has been considered as the single factor most frequently responsible for causing enamel mottling. However, in humans, either endogenous and/or exogenous factors not related to fluoride exposure may also cause enamel mottling. In this sense, various studies in the international literature have reported severe mottling of the teeth that could not be attributed to fluoride exposure. Thus, misdiagnosis of non-fluoride-induced enamel defects may occur frequently. Reports of unexpectedly high population prevalence and individual cases of fluorosis, where such diagnoses are irreconcilable with the identified fluoride history, highlight the necessity for a more precise definition and diagnosis of dental fluorosis. Also, a more discriminating diagnostic procedure is suggested. Particularly, positive identification of environmental fluoride levels to which the communities and individuals are exposed shall be developed before the confirmation of a diagnosis of fluorosis. It is considered that a more critical methodology for the diagnosis of fluorosis will be helpful in the rational use and control of fluorides for dental health, and in the identification of factors that may induce enamel defects.
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Affiliation(s)
- Inés A Revelo-Mejía
- Faculty of Odontology, Universidad Antonio Nariño, Popayán, Bogotá D.C., Colombia
| | - Arturo Hardisson
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Carmen Rubio
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Ángel J Gutiérrez
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain
| | - Soraya Paz
- Department of Toxicology, Universidad de La Laguna, La Laguna, Tenerife, Canary Islands, Spain.
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Cunningham JEA, McCague H, Malin AJ, Flora D, Till C. Fluoride exposure and duration and quality of sleep in a Canadian population-based sample. Environ Health 2021; 20:16. [PMID: 33602214 PMCID: PMC7893939 DOI: 10.1186/s12940-021-00700-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 02/03/2021] [Indexed: 05/31/2023]
Abstract
BACKGROUND Fluoride from dietary and environmental sources may concentrate in calcium-containing regions of the body such as the pineal gland. The pineal gland synthesizes melatonin, a hormone that regulates the sleep-wake cycle. We examined associations between fluoride exposure and sleep outcomes among older adolescents and adults in Canada. METHODS We used population-based data from Cycle 3 (2012-2013) of the Canadian Health Measures Survey. Participants were aged 16 to 79 years and 32% lived in communities supplied with fluoridated municipal water. Urinary fluoride concentrations were measured in spot samples and adjusted for specific gravity (UFSG; n = 1303) and water fluoride concentrations were measured in tap water samples among those who reported drinking tap water (n = 1016). We used multinomial and ordered logistic regression analyses (using both unweighted and survey-weighted data) to examine associations of fluoride exposure with self-reported sleep outcomes, including sleep duration, frequency of sleep problems, and daytime sleepiness. Covariates included age, sex, ethnicity, body mass index, chronic health conditions, and household income. RESULTS Median (IQR) UFSG concentration was 0.67 (0.63) mg/L. Median (IQR) water fluoride concentration was 0.58 (0.27) mg/L among participants living in communities supplied with fluoridated municipal water and 0.01 (0.06) mg/L among those living in non-fluoridated communities. A 0.5 mg/L higher water fluoride level was associated with 34% higher relative risk of reporting sleeping less than the recommended duration for age [unweighted: RRR = 1.34, 95% CI: 1.03, 1.73; p = .026]; the relative risk was higher, though less precise, using survey-weighted data [RRR = 1.96, 95% CI: 0.99, 3.87; p = .05]. UFSG was not significantly associated with sleep duration. Water fluoride and UFSG concentration were not significantly associated with frequency of sleep problems or daytime sleepiness. CONCLUSIONS Fluoride exposure may contribute to sleeping less than the recommended duration among older adolescents and adults in Canada.
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Affiliation(s)
| | - Hugh McCague
- Institute for Social Research, York University, Toronto, Ontario Canada
| | - Ashley J. Malin
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY USA
| | - David Flora
- Faculty of Health, York University, Toronto, Ontario Canada
| | - Christine Till
- Faculty of Health, York University, Toronto, Ontario Canada
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Rajmohan N, Masoud MHZ, Niyazi BAM. Assessment of groundwater quality and associated health risk in the arid environment, Western Saudi Arabia. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:9628-9646. [PMID: 33155113 DOI: 10.1007/s11356-020-11383-x] [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: 06/11/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
Groundwater quality and associated health risk in the arid environment, Rabigh basin, Western Saudi Arabia, was assessed using an integrated approach namely groundwater suitability zone (GWSZ) maps, drinking water quality index (DWQI), irrigation water quality (IWQ) parameters, irrigation water quality index (IWQI), chronic daily index (CDI), and hazard quotient (HQ). Groundwater samples were collected (n = 50) and analysed. Groundwater is alkaline (80%), fresh to brackish, and hard to very hard, and 78% of samples exceeded the international drinking water safe limit. The DWQI indicates that groundwater samples are excellent (24%), good (24%), poor (20%), very poor (10%), and unsuitable (22%) classes for drinking use. Total HQ (HQoral F- + HQoral NO3-) indicated that 68%, 80%, and 72% of samples express non-carcinogenic health threat to adult, children, and infant, respectively, in the study region. IWQ parameters, namely, EC, sodium adsorption ratio (SAR), Kelly's ratio (KR), sodium percentage (Na%), permeability index (PI), and magnesium hazard (MH), suggest that 72%, 66%, 64%, 98%, and 92% of samples have SAR < 6, KR < 1, MH < 50, PI > 25%, and Na% < 60%, respectively, which are suitable for irrigation. USSL classification implies that groundwater is suitable only for salt-tolerant crops and high permeability soil. IWQI values suggest that groundwater in 12%, 82%, and 6% of wells are low, medium, and highly suitable, respectively, for irrigation. Furthermore, only 42% of samples are recommended for livestock uses due to high F- (> 2). GWSZ maps, DWQI, and IWQI imply that groundwater in the upstream region is suitable whereas groundwater in the downstream is not recommended for any uses. Hence, this study recommended proper groundwater augmentation methods to reduce the salinity and improve the water quality in the shallow aquifer in the arid environment. The GWSZ, DWQI, and IWQI maps will aid to identify the suitable zones for groundwater development and sustainable management.
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Affiliation(s)
- Natarajan Rajmohan
- Water Research Center, King Abdulaziz University, P.O. Box 80200, Jeddah, 21598, Saudi Arabia.
| | - Milad H Z Masoud
- Water Research Center, King Abdulaziz University, P.O. Box 80200, Jeddah, 21598, Saudi Arabia
| | - Burhan A M Niyazi
- Water Research Center, King Abdulaziz University, P.O. Box 80200, Jeddah, 21598, Saudi Arabia
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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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Wang M, Liu L, Li H, Li Y, Liu H, Hou C, Zeng Q, Li P, Zhao Q, Dong L, Zhou G, Yu X, Liu L, Guan Q, Zhang S, Wang A. Thyroid function, intelligence, and low-moderate fluoride exposure among Chinese school-age children. ENVIRONMENT INTERNATIONAL 2020; 134:105229. [PMID: 31698198 DOI: 10.1016/j.envint.2019.105229] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 09/25/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Thyroid hormones (THs) are critical for brain development. Whether low-moderate fluoride exposure affects thyroid function and what the impact is on children's intelligence remain elusive. OBJECTIVES We conducted a cross-sectional study to examine the associations between low-moderate fluoride exposure and thyroid function in relation to children's intelligence. METHODS We recruited 571 resident children, aged 7-13 years, randomly from endemic and non-endemic fluorosis areas in Tianjin, China. We measured fluoride concentrations in drinking water and urine using the national standardized ion selective electrode method. Thyroid function was evaluated through the measurements of basal THs [(total triiodothyronine (TT3), total thyronine (TT4), free triiodothyronine (FT3), free thyronine (FT4)] and thyroid-stimulating hormone (TSH) levels in serum. Multivariable linear and logistical regression models were used to assess associations among fluoride exposure, thyroid function and IQ scores. RESULTS In adjusted models, every 1 mg/L increment of water fluoride was associated with 0.13 uIU/mL increase in TSH. Every 1 mg/L increment of urinary fluoride was associated with 0.09 ug/dL decrease in TT4, 0.009 ng/dL decrease in FT4 and 0.11 uIU/mL increase in TSH. Fluoride exposure was inversely related to IQ scores (B = -1.587; 95% CI: -2.607, -0.568 for water fluoride and B = -1.214; 95% CI: -1.987, -0.442 for urinary fluoride). Higher TT3, FT3 were related to the increased odds of children having high normal intelligence (OR = 3.407, 95% CI: 1.044, 11.120 for TT3; OR = 3.277, 95% CI: 1.621, 6.623 for FT3). We detected a significant modification effect by TSH on the association between urinary fluoride and IQ scores, without mediation by THs. CONCLUSIONS Our study suggests low-moderate fluoride exposure is associated with alterations in childhood thyroid function that may modify the association between fluoride and intelligence.
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Affiliation(s)
- 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
| | - Ling Liu
- 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
| | - Huijun Li
- Department of Laboratory Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 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
| | - Qiang Zeng
- Tianjin Centers for Disease Control and Prevention, Tianjin, 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
| | - 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
| | - 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
| | - 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
| | - 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
| | - Qing Guan
- Department of Laboratory Medicine, Tongji Hospital, 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.
| | - 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.
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Grandjean P. Developmental fluoride neurotoxicity: an updated review. Environ Health 2019; 18:110. [PMID: 31856837 PMCID: PMC6923889 DOI: 10.1186/s12940-019-0551-x] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 12/06/2019] [Indexed: 05/23/2023]
Abstract
BACKGROUND After the discovery of fluoride as a caries-preventing agent in the mid-twentieth century, fluoridation of community water has become a widespread intervention, sometimes hailed as a mainstay of modern public health. However, this practice results in elevated fluoride intake and has become controversial for two reasons. First, topical fluoride application in the oral cavity appears to be a more direct and appropriate means of preventing caries. Second, systemic fluoride uptake is suspected of causing adverse effects, in particular neurotoxicity during early development. The latter is supported by experimental neurotoxicity findings and toxicokinetic evidence of fluoride passing into the brain. METHOD An integrated literature review was conducted on fluoride exposure and intellectual disability, with a main focus on studies on children published subsequent to a meta-analysis from 2012. RESULTS Fourteen recent cross-sectional studies from endemic areas with naturally high fluoride concentrations in groundwater supported the previous findings of cognitive deficits in children with elevated fluoride exposures. Three recent prospective studies from Mexico and Canada with individual exposure data showed that early-life exposures were negatively associated with children's performance on cognitive tests. Neurotoxicity appeared to be dose-dependent, and tentative benchmark dose calculations suggest that safe exposures are likely to be below currently accepted or recommended fluoride concentrations in drinking water. CONCLUSION The recent epidemiological results support the notion that elevated fluoride intake during early development can result in IQ deficits that may be considerable. Recognition of neurotoxic risks is necessary when determining the safety of fluoride-contaminated drinking water and fluoride uses for preventive dentistry purposes.
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Affiliation(s)
- Philippe Grandjean
- Department of Environmental Health, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
- Department of Public Health, University of Southern Denmark, Odense, Denmark.
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Malin AJ, Bose S, Busgang SA, Gennings C, Thorpy M, Wright RO, Wright RJ, Arora M. Fluoride exposure and sleep patterns among older adolescents in the United States: a cross-sectional study of NHANES 2015-2016. Environ Health 2019; 18:106. [PMID: 31818308 PMCID: PMC6902325 DOI: 10.1186/s12940-019-0546-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/15/2019] [Indexed: 05/08/2023]
Abstract
BACKGROUND Fluoride from environmental sources accumulates preferentially in the pineal gland which produces melatonin, the hormone that regulates the sleep-wake cycle. However, the effects of fluoride on sleep regulation remain unknown. This population-based study examined whether chronic low-level fluoride exposure is associated with sleep patterns and daytime sleepiness among older adolescents in the United States (US). METHOD This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (2015-2016). We analyzed data from adolescents who had plasma fluoride (n = 473) and water fluoride (n = 419) measures and were not prescribed medication for sleep disorders. Relationships between fluoride exposure and self-reported sleep patterns or daytime sleepiness were examined using survey-weighted linear, binomial logistic or multinomial logistic regression after covariate adjustment. A Holm-Bonferroni correction accounted for multiple comparisons. RESULTS The average age of adolescents was 17 years (range = 16-19). Median (IQR) water and plasma fluoride concentrations were 0.27 (0.52) mg/L and 0.29 (0.19) μmol/L respectively. An IQR increase in water fluoride was associated with 1.97 times higher odds of reporting symptoms suggestive of sleep apnea (95% CI: 1.27, 3.05; p = 0.02), a 24 min later bedtime (B = 0.40, 95% CI: 0.10, 0.70; p = 0.05), a 26 min later morning wake time (B = 0.43, 95% CI: 0.13, 0.73; p = 0.04), and among males, a 38% reduction in the odds of reporting snoring (95% CI: 0.45, 0.87, p = 0.03). CONCLUSIONS Fluoride exposure may contribute to changes in sleep cycle regulation and sleep behaviors among older adolescents in the US. Additional prospective studies are warranted to examine the effects of fluoride on sleep patterns and determine critical windows of vulnerability for potential effects.
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Affiliation(s)
- Ashley J Malin
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Sonali Bose
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Division of Pulmonary, Critical Care and Sleep Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Stefanie A Busgang
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Chris Gennings
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Michael Thorpy
- The Saul R. Korey Department of Neurology, Albert Einstein College of Medicine, New York, NY, USA
| | - Robert O Wright
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Rosalind J Wright
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Manish Arora
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Elumalai V, Nwabisa DP, Rajmohan N. Evaluation of high fluoride contaminated fractured rock aquifer in South Africa - Geochemical and chemometric approaches. CHEMOSPHERE 2019; 235:1-11. [PMID: 31254776 DOI: 10.1016/j.chemosphere.2019.06.065] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/15/2019] [Accepted: 06/09/2019] [Indexed: 06/09/2023]
Abstract
The first systematic study on high fluoride contaminated fractured rock aquifer in South Africa using geochemical and chemometric approach is presented. Groundwater samples were collected from 49 boreholes and analysed for EC, pH, major and minor ions. The groundwater with high fluoride is associated with NaCl water types. The groundwater chemistry is governed by mineral weathering, evaporation and wastewater infiltration. PHREEQC modelling indicates that carbonate mineral saturation is decreasing with increasing salinity due to evaporation whereas fluorite saturation increases with increasing F being one of the prime controlling factors. Silicate minerals namely chalcedony, quartz and talc express saturation and over-saturation while chrysotile and sepiolite are undersaturated in most of the samples. PCA provided four factors and justified the role of mineral weathering, evaporation, ion exchange, longer residence time and anthropogenic impacts on water chemistry. R-mode and Q-mode cluster analysis resulted in four clusters. In cluster 1, (29%) of groundwater is less mineralized due to recent recharge. In cluster 2 (45%), groundwater chemistry is governed by weathering of silicates and fluorite minerals. Cluster 3 (20%) reveals the impact of anthropogenic activities and induced mineral weathering. Cluster 4 shows high EC, TDS, major ions, F and low HCO3 implying that groundwater is affected by evaporation and longer residence time promoting mineral-water interaction and precipitation of carbonate minerals. More than 50% of the study area is degraded due to fluoride contamination which requires proper remedial actions and further investigations on human health risk due to impact of fluoride contamination in groundwater is recommended.
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Affiliation(s)
| | - Dlamini P Nwabisa
- Department of Hydrology, University of Zululand, Kwa Dlangezwa, 3886, South Africa
| | - Natarajan Rajmohan
- Water Research Center, King Abdulaziz University, Jeddah, 21598, Saudi Arabia.
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Waugh DT. Fluoride Exposure Induces Inhibition of Sodium-and Potassium-Activated Adenosine Triphosphatase (Na +, K +-ATPase) Enzyme Activity: Molecular Mechanisms and Implications for Public Health. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E1427. [PMID: 31010095 PMCID: PMC6518254 DOI: 10.3390/ijerph16081427] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 04/02/2019] [Accepted: 04/08/2019] [Indexed: 12/24/2022]
Abstract
In this study, several lines of evidence are provided to show that Na + , K + -ATPase activity exerts vital roles in normal brain development and function and that loss of enzyme activity is implicated in neurodevelopmental, neuropsychiatric and neurodegenerative disorders, as well as increased risk of cancer, metabolic, pulmonary and cardiovascular disease. Evidence is presented to show that fluoride (F) inhibits Na + , K + -ATPase activity by altering biological pathways through modifying the expression of genes and the activity of glycolytic enzymes, metalloenzymes, hormones, proteins, neuropeptides and cytokines, as well as biological interface interactions that rely on the bioavailability of chemical elements magnesium and manganese to modulate ATP and Na + , K + -ATPase enzyme activity. Taken together, the findings of this study provide unprecedented insights into the molecular mechanisms and biological pathways by which F inhibits Na + , K + -ATPase activity and contributes to the etiology and pathophysiology of diseases associated with impairment of this essential enzyme. Moreover, the findings of this study further suggest that there are windows of susceptibility over the life course where chronic F exposure in pregnancy and early infancy may impair Na + , K + -ATPase activity with both short- and long-term implications for disease and inequalities in health. These findings would warrant considerable attention and potential intervention, not to mention additional research on the potential effects of F intake in contributing to chronic disease.
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Affiliation(s)
- Declan Timothy Waugh
- EnviroManagement Services, 11 Riverview, Doherty's Rd, P72 YF10 Bandon, Co. Cork, Ireland.
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25
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Waugh DT. Fluoride Exposure Induces Inhibition of Sodium/Iodide Symporter (NIS) Contributing to Impaired Iodine Absorption and Iodine Deficiency: Molecular Mechanisms of Inhibition and Implications for Public Health. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2019; 16:E1086. [PMID: 30917615 PMCID: PMC6466022 DOI: 10.3390/ijerph16061086] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/19/2019] [Accepted: 03/21/2019] [Indexed: 12/24/2022]
Abstract
The sodium iodide symporter (NIS) is the plasma membrane glycoprotein that mediates active iodide transport in the thyroid and other tissues, such as the salivary, gastric mucosa, rectal mucosa, bronchial mucosa, placenta and mammary glands. In the thyroid, NIS mediates the uptake and accumulation of iodine and its activity is crucial for the development of the central nervous system and disease prevention. Since the discovery of NIS in 1996, research has further shown that NIS functionality and iodine transport is dependent on the activity of the sodium potassium activated adenosine 5'-triphosphatase pump (Na+, K+-ATPase). In this article, I review the molecular mechanisms by which F inhibits NIS expression and functionality which in turn contributes to impaired iodide absorption, diminished iodide-concentrating ability and iodine deficiency disorders. I discuss how NIS expression and activity is inhibited by thyroglobulin (Tg), tumour necrosis factor alpha (TNF-α), transforming growth factor beta 1 (TGF-β1), interleukin 6 (IL-6) and Interleukin 1 beta (IL-1β), interferon-γ (IFN-γ), insulin like growth factor 1 (IGF-1) and phosphoinositide 3-kinase (PI3K) and how fluoride upregulates expression and activity of these biomarkers. I further describe the crucial role of prolactin and megalin in regulation of NIS expression and iodine homeostasis and the effect of fluoride in down regulating prolactin and megalin expression. Among many other issues, I discuss the potential conflict between public health policies such as water fluoridation and its contribution to iodine deficiency, neurodevelopmental and pathological disorders. Further studies are warranted to examine these associations.
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Affiliation(s)
- Declan Timothy Waugh
- EnviroManagement Services, 11 Riverview, Doherty's Rd, Bandon, Co. Cork, P72 YF10, Ireland.
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Razvi S, Korevaar TIM, Taylor P. Trends, Determinants, and Associations of Treated Hypothyroidism in the United Kingdom, 2005-2014. Thyroid 2019; 29:174-182. [PMID: 30501570 DOI: 10.1089/thy.2018.0251] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Recent reports suggest that prescriptions for thyroid hormones have increased. Recent trends in and determinants of the prevalence of treated hypothyroidism across the United Kingdom were therefore analyzed. METHODS Data covering the whole of the United Kingdom held by the National Health Service and the Office of National Statistics were examined. The main outcome measured was trends in the prevalence of treated hypothyroidism between 2005 and 2014. In addition, linear trend forecasting was performed to estimate projected trends in the prevalence of treated hypothyroidism up to the year 2025. Furthermore, determinants of variation of treated hypothyroidism prevalence across each of the 237 health areas in the United Kingdom in 2014 and its association with other health conditions were explored by multivariate linear regression analyses. RESULTS The prevalence of treated hypothyroidism increased from 2.3% (1.4 million) to 3.5% (2.2 million) of the total British population between the years 2005 and 2014 and is projected to rise further to 4.2% (2.9 million) by 2025. There was large geographical variation of treated hypothyroidism across the United Kingdom, with London having the lowest (1.4%) and the Western Isles of Scotland having the highest (6.3%) prevalence. This variation was attenuated, but did not completely disappear, after some potential determinants were accounted for. The prevalence of treated hypothyroidism was independently related to health areas, with a higher proportion of individuals who were female, white, and obese, and negatively associated with prevalent cigarette smoking. The prevalence of treated hypothyroidism was significantly associated with the frequency of prevalent atrial fibrillation but not with other major health conditions, including ischemic heart disease and osteoporosis. CONCLUSIONS Between 2005 and 2014, the prevalence of treated hypothyroidism increased across the United Kingdom, has wide geographical variation, and is likely to increase further for the foreseeable future. Clinical effects and cost-effectiveness of the trend in increasing treatment of hypothyroidism remains to be evaluated.
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Affiliation(s)
- Salman Razvi
- 1 Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
- 2 Department of Endocrinology, Gateshead Health NHS Foundation Trust, Gateshead, United Kingdom
| | - Tim I M Korevaar
- 3 Rotterdam Thyroid Centre, Erasmus Medical Centre, Rotterdam, The Netherlands
| | - Peter Taylor
- 4 Thyroid Research Group, Systems Immunity Research Institute, Cardiff University School of Medicine, Cardiff, United Kingdom
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Shaik N, Shanbhog R, Nandlal B, Tippeswamy HM. Fluoride and Thyroid Function in Children Resident of Naturally Fluoridated Areas Consuming Different Levels of Fluoride in Drinking Water: An Observational Study. Contemp Clin Dent 2019; 10:24-30. [PMID: 32015637 PMCID: PMC6974988 DOI: 10.4103/ccd.ccd_108_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: Literature shows association between systemic fluorides and endocrine disorders especially related to thyroid, with lack of clarity. Aims and Objectives: The aim and objective of this study was to estimate serum triiodothyronine (T3), thyroxin, thyroid-stimulating hormone (TSH), fluoride, calcium, phosphate, and alkaline phosphatase levels among children with normal nutritional status and optimal iodine intake residing in three different ranges of drinking water fluoride levels. Materials and Methods: The present double-blinded, observational trial comprised of 293 children aged between 9 and 13 years consuming naturally fluoridated water of three different ranges: Group I: 0.01–0.6 parts per million (ppm), Group II: 0.7–1.2 ppm, and Group III: 1.3–1.8 ppm. For each child's demographic data, body mass index and Clinical Fluorosis Index were recorded along with serum T3, T4, TSH, fluoride, calcium, phosphate, and serum alkaline phosphatase levels. Data were analyzed using Chi–square test, Kruskal–Wallis test, and repeated measures ANOVA with SPSS 23. Results: For serum TSH levels, 40% of children in Group I had deranged levels followed by Group III (20%) and Group II (16%). For serum T4 levels, 24% of children of both Groups I and III had deranged levels followed by Group II (20%). Intergroup correlation of drinking water fluoride levels to the number of deranged serum T3, T4, and TSH of the children showed nonsignificant association. Serum T3, calcium, phosphate, and alkaline phosphatase levels in all children showed values falling within normal range. Conclusion: According to the present study results, long-term intake of fluoridated drinking water (0.02–1.4 ppm) did not show effect on the thyroid function in children with normal nutritional status and optimal iodine intake.
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Affiliation(s)
- Naseemoon Shaik
- Department of Pediatric Dentistry, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
| | - Raghavendra Shanbhog
- Department of Pediatric Dentistry, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
| | - B Nandlal
- Department of Pediatric Dentistry, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
| | - H M Tippeswamy
- Department of Public Health Dentistry, JSS Dental College and Hospital, JSS Academy of Higher Education and Research, Mysore, Karnataka, India
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Malin AJ, Riddell J, McCague H, Till C. Fluoride exposure and thyroid function among adults living in Canada: Effect modification by iodine status. ENVIRONMENT INTERNATIONAL 2018; 121:667-674. [PMID: 30316182 DOI: 10.1016/j.envint.2018.09.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 09/14/2018] [Accepted: 09/14/2018] [Indexed: 05/23/2023]
Abstract
BACKGROUND Fluoride exposure has the potential to disrupt thyroid functioning, though adequate iodine intake may mitigate this effect. This is the first population-based study to examine the impact of chronic low-level fluoride exposure on thyroid function, while considering iodine status. The objective of this study was to determine whether urinary iodine status modifies the effect of fluoride exposure on thyroid stimulating hormone (TSH) levels. METHODS This cross-sectional study utilized weighted population-based data from Cycle 3 (2012-2013) of the Canadian Health Measures Survey (CHMS). Information was collected via a home interview and a visit to a mobile examination centre. The weighted sample represented 6,914,124 adults in Canada aged 18-79 who were not taking any thyroid-related medication. Urinary fluoride concentrations were measured in spot samples using an ion selective electrode and adjusted for specific gravity (UFSG). Serum TSH levels provided a measure of thyroid function. Multivariable regression analyses examined the relationship between UFSG and TSH, controlling for covariates. RESULTS Approximately 17.8% of participants fell in the moderately-to-severely iodine deficient range. The mean (SD) age of the sample was 46.5 (15.6) years and the median UFSG concentration was 0.74 mg/L. Among iodine deficient adults, a 1 mg/L increase in UFSG was associated with a 0.35 mIU/L increase in TSH [95% CI: 0.06, 0.64; p = 0.01, one-tailed]. CONCLUSIONS Adults living in Canada who have moderate-to-severe iodine deficiencies and higher levels of urinary fluoride may be at an increased risk for underactive thyroid gland activity.
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Affiliation(s)
- Ashley J Malin
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1057, New York 10029, NY, USA; Psychology Department, Faculty of Health, York University, 4700 Keele St, Toronto M3J 1P3, ON, Canada.
| | - Julia Riddell
- Psychology Department, Faculty of Health, York University, 4700 Keele St, Toronto M3J 1P3, ON, Canada.
| | - Hugh McCague
- Institute for Social Research, York University, 242A-4700 Keele St, Toronto, ON, Canada, M3J 1P3.
| | - Christine Till
- Psychology Department, Faculty of Health, York University, 4700 Keele St, Toronto M3J 1P3, ON, Canada.
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Mikkonen HG, van de Graaff R, Mikkonen AT, Clarke BO, Dasika R, Wallis CJ, Reichman SM. Environmental and anthropogenic influences on ambient background concentrations of fluoride in soil. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 242:1838-1849. [PMID: 30082154 DOI: 10.1016/j.envpol.2018.07.083] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 06/08/2023]
Abstract
Excess exposure to fluoride causes substantive health burden in humans and livestock globally. However, few studies have assessed the distribution and controls of variability of ambient background concentrations of fluoride in soil. Ambient background concentrations of fluoride in soil were collated for Greater Melbourne, Greater Geelong, Ballarat and Mitchell in Victoria, Australia (n = 1005). Correlation analysis and machine learning techniques were used to identify environmental and anthropogenic influences of fluoride variability in soil. Sub-soils (>0.3 m deep), in some areas overlying siltstone and sandstone, and to a lesser extent, overlying basalt, were naturally enriched with fluoride at concentrations above ecological thresholds for grazing animals. Soil fluoride enrichment was predominantly influenced by parent material (mineralogy), precipitation (illuviation), leaching during palaeoclimates and marine inputs. Industrial air pollution did not significantly influence ambient background concentrations of fluoride at a regional scale. However, agricultural practices (potentially the use of phosphate fertilisers) were indicated to have resulted in added fluoride to surface soils overlying sediments. Geospatial variables alone were not sufficient to accurately model ambient background soil fluoride concentrations. A multiple regression model based on soil chemistry and parent material was shown to accurately predict ambient background fluoride concentrations in soils and support assessment of fluoride enrichment in the environment.
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Affiliation(s)
- Hannah G Mikkonen
- School of Engineering, RMIT University, Melbourne, Victoria, Australia; Centre for Environmental Sustainability and Remediation, RMIT University, Victoria, Australia; CDM Smith, Richmond, Victoria, Australia
| | | | | | - Bradley O Clarke
- Centre for Environmental Sustainability and Remediation, RMIT University, Victoria, Australia; School of Science, RMIT University, Victoria, Australia
| | - Raghava Dasika
- Australian Contaminated Land Consultants Association, Victoria, Australia
| | | | - Suzie M Reichman
- School of Engineering, RMIT University, Melbourne, Victoria, Australia; Centre for Environmental Sustainability and Remediation, RMIT University, Victoria, Australia.
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Kheradpisheh Z, Mahvi AH, Mirzaei M, Mokhtari M, Azizi R, Fallahzadeh H, Ehrampoush MH. Correlation between drinking water fluoride and TSH hormone by ANNs and ANFIS. JOURNAL OF ENVIRONMENTAL HEALTH SCIENCE AND ENGINEERING 2018; 16:11-18. [PMID: 30258638 PMCID: PMC6148227 DOI: 10.1007/s40201-018-0290-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 02/10/2018] [Indexed: 01/13/2023]
Abstract
Background Artificial neural networks (ANNs) and adaptive neural-fuzzy Inference system (ANFIS) are the best solutions to finding the correlation between some water parameters and human hormones. The correlation between thyroid stimulating hormone (TSH) and drinking water fluoride studied by ANNS and ANFIS models in Yazd city. Method In this study, eighty people with thyroid gland disorder and 213 healthy people invited. Their thyroid hormones and fluoride drinking water analyzed. Results The result of ANFIS showed R2 = 0.81 for test and R2 = 0.85 for train in all cases and controls data. This results were R2 = 0.73 and R2 = 0.81 for ANNs respectively. Conclusion This models can be used as an alternative for show correlation between Drinking Water Fluoride and TSH Hormone and R2 = 0.85 gained from ANFIS was the best.
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Affiliation(s)
- Zohreh Kheradpisheh
- Environmental Science and Technology Research Center, Department of Environmental Health Engineering, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Amir Hossein Mahvi
- School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
- Center for Solid Waste Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Mirzaei
- Yazd Cardiovascular Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mehdi Mokhtari
- Environmental Science and Technology Research Center, Department of Environmental Health Engineering, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Reyhane Azizi
- Department of Endocrinology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Hossein Fallahzadeh
- Department of Biostatistics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohammad Hassan Ehrampoush
- Environmental Science and Technology Research Center, Department of Environmental Health Engineering, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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Helmi M, Spinella MK, Seymour B. Community water fluoridation online: an analysis of the digital media ecosystem. J Public Health Dent 2018; 78:296-305. [PMID: 29603251 DOI: 10.1111/jphd.12268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 02/13/2018] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Research demonstrates the safety and efficacy of community water fluoridation (CWF). Yet, the digitization of communication has triggered the spread of inaccurate information online. The purpose of this study was to analyze patterns of CWF information dissemination by a network of sources on the web. METHODS We used Media Cloud, a searchable big data platform of over 550 million stories from 50 thousand sources, along with tools to analyze that archive. We generated a network of fluoridation publishers using Media Cloud's keyword identification from August 1, 2015 to July 31, 2016. We defined the media type and sentiment toward CWF for each source and generated a network map of the most influential sources during our study period based on hyperlinking activity. RESULTS Media Cloud detected a total of 980 stories from 325 different sources related to water fluoridation. We identified nine different media types participating in the dissemination of information: academic, government, scientific group, natural medicine, blogs, mainstream media, advocacy groups, user-generated (e.g., YouTube), and "other." We detected five sub-networks within the overall fluoridation network map, each with its own characteristics. Twenty-one percent of sources were pro-fluoridation, receiving 57 percent of all inlinks, 22 percent of sources were anti-fluoridation, and the rest were neutral (54 percent). CONCLUSIONS The dominant neutral sentiment of the network may signify that anti- and pro-sides of the debate are viewed as balanced, not just in number but also in quality of information. Despite high inlinks to pro-sources, anti-fluoridation sentiment maintains influence online.
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Affiliation(s)
- Mohammad Helmi
- Harvard School of Dental Medicine, Oral Health Policy and Epidemiology, Boston, MA, USA.,King Saud University, College of Dentistry, Periodontics and Community Dentistry, Riyadh, Kingdom of Saudi Arabia
| | - Mary Kate Spinella
- Harvard School of Dental Medicine, Oral Health Policy and Epidemiology, Boston, MA, USA
| | - Brittany Seymour
- Harvard School of Dental Medicine, Oral Health Policy and Epidemiology, Boston, MA, USA
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Impact of Drinking Water Fluoride on Human Thyroid Hormones: A Case- Control Study. Sci Rep 2018; 8:2674. [PMID: 29422493 PMCID: PMC5805681 DOI: 10.1038/s41598-018-20696-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 01/21/2018] [Indexed: 12/07/2022] Open
Abstract
The elevated fluoride from drinking water impacts on T3, T4 and TSH hormones. The aim was study impacts of drinking water fluoride on T3, T4 and TSH hormones inYGA (Yazd Greater Area). In this case- control study 198 cases and 213 controls were selected. Fluoride was determined by the SPADNS Colorimetric Method. T3, T4 and TSH hormones tested in the Yazd central laboratory by RIA (Radio Immuno Assay) method. The average amount of TSH and T3 hormones based on the levels of fluoride in two concentration levels 0-0.29 and 0.3-0.5 (mg/L) was statistically significant (P = 0.001 for controls and P = 0.001 for cases). In multivariate regression logistic analysis, independent variable associated with Hypothyroidism were: gender (odds ratio: 2.5, CI 95%: 1.6-3.9), family history of thyroid disease (odds ratio: 2.7, CI 95%: 1.6-4.6), exercise (odds ratio: 5.34, CI 95%: 3.2-9), Diabetes (odds ratio: 3.7, CI 95%: 1.7-8), Hypertension (odds ratio: 3.2, CI 95%: 1.3-8.2), water consumption (odds ratio: 4, CI 95%: 1.2-14). It was found that fluoride has impacts on TSH, T3 hormones even in the standard concentration of less than 0.5 mg/L. Application of standard household water purification devices was recommended for hypothyroidism.
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Barberio AM, Hosein FS, Quiñonez C, McLaren L. Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation. J Epidemiol Community Health 2017; 71:1019-1025. [PMID: 28839078 PMCID: PMC5754860 DOI: 10.1136/jech-2017-209129] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/29/2017] [Accepted: 07/08/2017] [Indexed: 02/02/2023]
Abstract
Background There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. Methods We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. Results There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. Conclusion These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist.
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Affiliation(s)
- Amanda M Barberio
- Department of Cancer Epidemiology and Prevention Research, Alberta Health Services, Calgary, Alberta, Canada.,Department of Community Health Sciences and O'Brien Institute for Public Health, University of Calgary, Calgary, Alberta, Canada
| | - F Shaun Hosein
- Faculty of Medicine, University of Queensland, Herston, Queensland, Australia
| | - Carlos Quiñonez
- Dental Public Health, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Lindsay McLaren
- Department of Community Health Sciences and O'Brien Institute for Public Health, University of Calgary, Calgary, Alberta, Canada
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Bobak M, Dunn JR. Editorial note: Peckham versus Newton. Br J Soc Med 2017; 71:317. [DOI: 10.1136/jech-2016-208773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Newton JN, Verne J, Dancox M, Young N. Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? Comments on the authors' response to earlier criticism. J Epidemiol Community Health 2017; 71:315-316. [PMID: 28093451 PMCID: PMC5484025 DOI: 10.1136/jech-2016-208649] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 11/18/2016] [Indexed: 11/03/2022]
Affiliation(s)
- John N Newton
- Department of Chief Knowledge Officer, Public Health England, London, UK
| | - Julia Verne
- Department of South West Knowledge and Intelligence Team, Public Health England, Bristol, UK
| | - Mark Dancox
- Department of South West Knowledge and Intelligence Team, Public Health England, Bristol, UK
| | - Nicholas Young
- Department of Knowledge and Intelligence Team, Public Health England, Bristol, UK
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Fluegge K. Community water fluoridation predicts increase in age-adjusted incidence and prevalence of diabetes in 22 states from 2005 and 2010. JOURNAL OF WATER AND HEALTH 2016; 14:864-877. [PMID: 27740551 PMCID: PMC5116242 DOI: 10.2166/wh.2016.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Community water fluoridation is considered a significant public health achievement of the 20th century. In this paper, the hypothesis that added water fluoridation has contributed to diabetes incidence and prevalence in the United States was investigated. Panel data from publicly available sources were used with population-averaged models to test the associations of added and natural fluoride on the outcomes at the county level in 22 states for the years 2005 and 2010. The findings suggest that a 1 mg increase in the county mean added fluoride significantly positively predicts a 0.23 per 1,000 person increase in age-adjusted diabetes incidence (P < 0.001), and a 0.17% increase in age-adjusted diabetes prevalence percent (P < 0.001), while natural fluoride concentration is significantly protective. For counties using fluorosilicic acid as the chemical additive, both outcomes were lower: by 0.45 per 1,000 persons (P < 0.001) and 0.33% (P < 0.001), respectively. These findings are adjusted for county-level and time-varying changes in per capita tap water consumption, poverty, year, population density, age-adjusted obesity and physical inactivity, and mean number of years since water fluoridation started. Sensitivity analyses revealed robust effects for both types of fluoride. Community water fluoridation is associated with epidemiological outcomes for diabetes.
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Affiliation(s)
- Kyle Fluegge
- Institute of Health and Environmental Research (IHER), Cleveland, OH, USA and Department of Epidemiology & Biostatistics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA E-mail:
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Newton JN, Young N, Verne J, Morris J. Water fluoridation and hypothyroidism: results of this study need much more cautious interpretation. J Epidemiol Community Health 2016; 69:617-8. [PMID: 26068199 PMCID: PMC4484260 DOI: 10.1136/jech-2015-205917] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
| | - Nick Young
- South West Knowledge and Intelligence Team, Public Health England, Bristol, UK
| | - Julia Verne
- South West Knowledge and Intelligence Team, Public Health England, Bristol, UK
| | - John Morris
- Dental Public Health, Public Health England, Birmingham, UK
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Waugh DT, Potter W, Limeback H, Godfrey M. Risk Assessment of Fluoride Intake from Tea in the Republic of Ireland and its Implications for Public Health and Water Fluoridation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:E259. [PMID: 26927146 PMCID: PMC4808922 DOI: 10.3390/ijerph13030259] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 11/16/2022]
Abstract
The Republic of Ireland (RoI) is the only European Country with a mandatory national legislation requiring artificial fluoridation of drinking water and has the highest per capita consumption of black tea in the world. Tea is a hyperaccumulator of fluoride and chronic fluoride intake is associated with multiple negative health outcomes. In this study, fifty four brands of the commercially available black tea bag products were purchased and the fluoride level in tea infusions tested by an ion-selective electrode method. The fluoride content in all brands tested ranged from 1.6 to 6.1 mg/L, with a mean value of 3.3 mg/L. According to our risk assessment it is evident that the general population in the RoI is at a high risk of chronic fluoride exposure and associated adverse health effects based on established reference values. We conclude that the culture of habitual tea drinking in the RoI indicates that the total cumulative dietary fluoride intake in the general population could readily exceed the levels known to cause chronic fluoride intoxication. Evidence suggests that excessive fluoride intake may be contributing to a wide range of adverse health effects. Therefore from a public health perspective, it would seem prudent and sensible that risk reduction measures be implemented to reduce the total body burden of fluoride in the population.
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Affiliation(s)
- Declan T Waugh
- EnviroManagement Services, 11 Riverview, Dohertys Rd, Bandon, Co. Cork P72 YF10, Ireland.
| | - William Potter
- Department of Chemistry and Biochemistry, KEH M2225, University of Tulsa, Tulsa, OK 74104-3189, USA.
| | - Hardy Limeback
- Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, ON M5G 1G6, Canada.
| | - Michael Godfrey
- Bay of Plenty Environmental Health, 1416A Cameron Road, Tauranga 3012, New Zealand.
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Abstract
In many countries around the world community water fluoridation is a key element in the campaign for better dental public health. Its safety and effectiveness have been confirmed through decades of research, and the practice has been strongly endorsed by reputable health authorities. A strong evidence base is critical for the implementation of fluoridation and other public health measures. Health professionals must ensure that the highest quality evidence is promoted, and weak evidence identified and discredited.
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40
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Grimes DR. Commentary on "Are fluoride levels in drinking water associated with hypothyroidism prevalence in England? A large observational study of GP practice data and fluoride levels in drinking water". J Epidemiol Community Health 2015; 69:616. [PMID: 25788719 DOI: 10.1136/jech-2015-205708] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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