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Zhang Y, Gao Y, Liu X. Focus on cognitive impairment induced by excessive fluoride: An update review. Neuroscience 2024; 558:22-29. [PMID: 39137871 DOI: 10.1016/j.neuroscience.2024.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 08/06/2024] [Accepted: 08/07/2024] [Indexed: 08/15/2024]
Abstract
Fluorosis is a global public health concern. Prolonged exposure to excessive fluoride causes fluoride accumulation in the hippocampus, resulting in cognitive dysfunction. Cell death is necessary for maintaining tissue function and morphology, and changes in the external morphology of nerve cells and the function of many internal organelles are typical features of cell death; however, it is also a typical feature of cognitive impairment caused by fluorosis. However, the pathogenesis of cognitive impairment caused by different degrees of fluoride exposure varies. Herein, we provide an overview of cognitive impairment caused by excessive fluoride exposure in different age groups, and the underlying mechanisms for cognitive impairment in various model organisms. The mechanisms underlying these impairments include oxidative stress, synaptic and neurotransmission dysfunction, disruption of mitochondrial and energy metabolism, and calcium channel dysregulation. This study aims to provide potential insights that serve as a reference for subsequent research on the cognitive function caused by excessive fluoride.
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Affiliation(s)
- Yuhang Zhang
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province 150081, China; Key Lab of Etiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health (23618504), Harbin, Heilongjiang 150081, China; Heilongjiang Provincial Key Lab of Trace Elements and Human Health, Harbin, Heilongjiang 150081, China
| | - Yanhui Gao
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province 150081, China; Key Lab of Etiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health (23618504), Harbin, Heilongjiang 150081, China; Heilongjiang Provincial Key Lab of Trace Elements and Human Health, Harbin, Heilongjiang 150081, China.
| | - Xiaona Liu
- Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin, Heilongjiang Province 150081, China; Key Lab of Etiology and Epidemiology, Education Bureau of Heilongjiang Province and Ministry of Health (23618504), Harbin, Heilongjiang 150081, China; Heilongjiang Provincial Key Lab of Trace Elements and Human Health, Harbin, Heilongjiang 150081, China.
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2
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Ruehlmann AK, Cecil KM, Lippert F, Yolton K, Ryan PH, Brunst KJ. Epigenome-wide association study of fluoride exposure during early adolescence and DNA methylation among U.S. children. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 948:174916. [PMID: 39038671 DOI: 10.1016/j.scitotenv.2024.174916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 07/18/2024] [Accepted: 07/18/2024] [Indexed: 07/24/2024]
Abstract
Exposure to fluoride in early childhood has been associated with altered cognition, intelligence, attention, and neurobehavior. Fluoride-related neurodevelopment effects have been shown to vary by sex and very little is known about the mechanistic processes involved. There is limited research on how fluoride exposure impacts the epigenome, potentially leading to changes in DNA methylation of specific genes regulating key developmental processes. In the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS), urine samples were analyzed using a microdiffusion method to determine childhood urinary fluoride adjusted for specific gravity (CUFsg) concentrations. Whole blood DNA methylation was assessed using the Infinium MethylationEPIC BeadChip 850 k Array. In a cross-sectional analysis, we interrogated epigenome-wide DNA methylation at 775,141 CpG loci across the methylome in relation to CUFsg concentrations in 272 early adolescents at age 12 years. Among all participants, higher concentrations of CUF were associated with differential methylation of one CpG (p < 6 × 10-8) located in the gene body of GBF1 (cg25435255). Among females, higher concentrations of CUFsg were associated with differential methylation of 7 CpGs; only three CpGs were differentially methylated among males with no overlap of significant CpGs observed among females. Secondary analyses revealed several differentially methylated regions (DMRs) and CpG loci mapping to genes with key roles in psychiatric outcomes, social interaction, and cognition, as well as immunologic and metabolic phenotypes. While fluoride exposure may impact the epigenome during early adolescence, the functional consequences of these changes are unclear warranting further investigation.
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Affiliation(s)
- Anna K Ruehlmann
- University of Cincinnati, College of Medicine, Department of Environmental and Public Health Sciences, Cincinnati, OH, USA
| | - Kim M Cecil
- University of Cincinnati, College of Medicine, Department of Environmental and Public Health Sciences, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Frank Lippert
- Department of Cariology, Operative Dentistry, and Dental Public Health, Oral Health Research Institute, Indiana University School of Dentistry, Indianapolis, IN, USA
| | - Kimberly Yolton
- University of Cincinnati, College of Medicine, Department of Environmental and Public Health Sciences, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA; Division of General and Community Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Patrick H Ryan
- University of Cincinnati, College of Medicine, Department of Environmental and Public Health Sciences, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA; Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Kelly J Brunst
- University of Cincinnati, College of Medicine, Department of Environmental and Public Health Sciences, Cincinnati, OH, USA.
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Ding G, Gao Y, Kan H, Zeng Q, Yan C, Li F, Jiang F, Landrigan PJ, Tian Y, Zhang J. Environmental exposure and child health in China. ENVIRONMENT INTERNATIONAL 2024; 187:108722. [PMID: 38733765 DOI: 10.1016/j.envint.2024.108722] [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: 12/26/2023] [Revised: 04/23/2024] [Accepted: 05/03/2024] [Indexed: 05/13/2024]
Abstract
Chinese children are exposed to broad environmental risks ranging from well-known hazards, such as pesticides and heavy metals, to emerging threats including many new man-made chemicals. Although anecdotal evidence suggests that the exposure levels in Chinese children are substantially higher than those of children in developed countries, a systematic assessment is lacking. Further, while these exposures have been linked to a variety of childhood diseases, such as respiratory, endocrine, neurological, behavioral, and malignant disorders, the magnitude of the associations is often unclear. This review provides a current epidemiologic overview of commonly reported environmental contaminants and their potential impact on children's health in China. We found that despite a large volume of studies on various topics, there is a need for more high-quality research and better-coordinated regional and national data collection. Moreover, prevention of such diseases will depend not only on training of environmental health professionals and enhanced research programs, but also on public education, legislation, and networking.
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Affiliation(s)
- Guodong Ding
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Pediatrics, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Yu Gao
- Department of Environmental Health, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Haidong Kan
- Key Lab of Public Health Safety of the Ministry of Education and NHC Key Laboratory of Health Technology Assessment, School of Public Health, Fudan University, Shanghai, China.
| | - Qiang Zeng
- Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China; Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, and State Key Laboratory of Environmental health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
| | - Chonghuai Yan
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Fei Li
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Developmental and Behavioral Pediatric & Child Primary Care, Brain and Behavioral Research Unit of Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Fan Jiang
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Developmental and Behavioral Pediatrics, National Children's Medical Center, Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Philip J Landrigan
- Global Observatory on Planetary Health, Boston College, Chestnut Hill, MA, United States; Centre Scientifique de Monaco, MC, Monaco.
| | - Ying Tian
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Environmental Health, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Jun Zhang
- Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; Department of Maternal and Child Health, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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India Aldana S, Colicino E, Cantoral Preciado A, Tolentino M, Baccarelli AA, Wright RO, Téllez Rojo MM, Valvi D. Longitudinal associations between early-life fluoride exposures and cardiometabolic outcomes in school-aged children. ENVIRONMENT INTERNATIONAL 2024; 183:108375. [PMID: 38128386 PMCID: PMC10842303 DOI: 10.1016/j.envint.2023.108375] [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: 07/12/2023] [Revised: 11/06/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND/AIM Fluoride is a natural mineral present in food, water, and dental products, constituting ubiquitous long-term exposure in early childhood and across the lifespan. Experimental evidence shows fluoride-induced lipid disturbances with potential implications for cardiometabolic health. However, epidemiological studies are scarce. For the first time, we evaluated associations between repeated fluoride measures and cardiometabolic outcomes in children. METHODS We studied ∼ 500 Mexican children from the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) cohort with measurements on urinary fluoride at age 4, and dietary fluoride at ages 4, 6, and 8 years approximately. We used covariate-adjusted linear mixed-effects and linear regression models to assess fluoride associations with multiple cardiometabolic outcomes (ages 4-8): lipids (total cholesterol, HDL, LDL, and triglycerides), glucose, HbA1c, adipokines (leptin and adiponectin), body fat, and age- and sex-specific z-scores of body mass index (zBMI), waist circumference, and blood pressure. RESULTS Dietary fluoride intake at age 4 was associated with annual increases in triglycerides [β per-fluoride-doubling = 2.02 (95 % CI: 0.37, 3.69)], cholesterol [β = 1.46 (95 % CI: 0.52, 2.39)], HDL [β = 0.39 (95 % CI: 0.02, 0.76)], LDL [β = 0.87 (95 % CI: 0.02, 1.71)], and HbA1c [β = 0.76 (95 % CI: 0.28, 1.24)], and decreased leptin [β = -3.58 (95 % CI: -6.34, -0.75)] between the ages 4 and 8. In cross-sectional analyses at age 8, higher tertiles of fluoride exposure were associated with increases in zBMI, triglycerides, glucose, and leptin (p-tertile trend < 0.05). Stronger associations were observed in boys at year 8 and in girls prior to year 8 (p-sex interaction < 0.05). Fewer but consistent associations were observed for urinary fluoride at age 4, indicating increased annual changes in HDL and HbA1c with higher fluoride levels. CONCLUSION Dietary fluoride exposures in early- and mid-childhood were associated with adverse cardiometabolic outcomes in school-aged children. Further research is needed to elucidate whether these associations persist at later ages.
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Affiliation(s)
- Sandra India Aldana
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Elena Colicino
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Maricruz Tolentino
- Department of Nutrition, National Institute of Perinatology, Mexico City, Mexico
| | - Andrea A Baccarelli
- Departments of Environmental Health Sciences and Epidemiology, Columbia University Mailman School of Public Health, 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
| | - Martha María Téllez Rojo
- Center for Nutrition and Health Research, National Institute of Public Health, Cuernavaca, Morelos, Mexico
| | - Damaskini Valvi
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Kumar JV, Moss ME, Liu H, Fisher-Owens S. Association between low fluoride exposure and children's intelligence: a meta-analysis relevant to community water fluoridation. Public Health 2023; 219:73-84. [PMID: 37120936 DOI: 10.1016/j.puhe.2023.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 03/05/2023] [Accepted: 03/13/2023] [Indexed: 05/02/2023]
Abstract
OBJECTIVES Previous meta-analyses have mainly focused on studies conducted in endemic fluorosis areas with relatively high fluoride concentrations. These are impoverished rural communities in China, India, and Iran, and the findings cannot be generalised to developed countries. Therefore, we investigated the association between fluoride concentrations relevant to community water fluoridation and children's cognition measured with IQ scores by synthesising effect sizes reported in observational studies. METHODS A previous meta-analysis and the National Toxicology Program database that included a search of multiple databases and the authors' search of PubMed, Google Scholar, and Mendeley provided the data. Cross-sectional and cohort studies examining the association between fluoride and children's cognition and intelligence scores were selected. Two reviewers abstracted data using standard procedures. We performed three meta-analyses to synthesise the effects using the random effects models. RESULTS Eight studies of standardized mean difference in IQ scores from non-endemic fluorosis areas found no statistically significant difference between recommended and lower levels of fluoride (standardized mean difference = 0.07; 95% confidence interval: -0.02, 0.17; I2 = 0%), and no significant fluctuation in IQ scores across the differences in fluoride concentrations by non-linear modeling with restricted cubic spline (P = 0.21). Meta-analyses of children's and maternal spot urinary fluoride associated pooled regression coefficients (Betachildren = 0.16; 95% confidence interval: -0.40, 0.73; P = 0.57; I2 = 0%, Betamaternal = -0.92; 95% CI: -3.29, 1.46; P = 0.45; I2 = 72%) were not statistically significant. Further regression analysis by standardizing absolute mean IQ scores from lower fluoride areas did not show a relationship between F concentration and IQ scores (Model Likelihood-ratio test: P-value = 0.34.) CONCLUSIONS: These meta-analyses show that fluoride exposure relevant to community water fluoridation is not associated with lower IQ scores in children. However, the reported association observed at higher fluoride levels in endemic areas requires further investigation.
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Affiliation(s)
- Jayanth V Kumar
- California Department of Public Health, MS 7208, 1616 Capitol Ave, Sacramento, CA 95814, USA.
| | - Mark E Moss
- ECU School of Dental Medicine, 1851 MacGregor Downs Road - MS 701, East Carolina University, Greenville, NC 27834-4354, USA
| | - Honghu Liu
- Public and Population Health, School of Dentistry, Department of Medicine, University of California, Los Angeles (UCLA), CA 90095, USA
| | - Susan Fisher-Owens
- School of Medicine and School of Dentistry, University of California, San Francisco, 1001 Potrero Ave, San Francisco, CA 94110, USA
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Avila-Rojas SH, Aparicio-Trejo OE, Sanchez-Guerra MA, Barbier OC. Effects of fluoride exposure on mitochondrial function: Energy metabolism, dynamics, biogenesis and mitophagy. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2022; 94:103916. [PMID: 35738460 DOI: 10.1016/j.etap.2022.103916] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 06/09/2022] [Accepted: 06/17/2022] [Indexed: 06/15/2023]
Abstract
Fluoride is ubiquitous in the environment. Furthermore, drinking water represents the main source of exposure to fluoride for humans. Interestingly, low fluoride concentrations have beneficial effects on bone and teeth development; however, chronic fluoride exposure has harmful effects on human health. Besides, preclinical studies associate fluoride toxicity with oxidative stress, inflammation, and apoptosis. On the other hand, it is well-known that mitochondria play a key role in reactive oxygen species production. By contrast, fluoride's effect on processes such as mitochondrial dynamics, biogenesis and mitophagy are little known. These processes modulate the size, content, and distribution of mitochondria and their depuration help to counter the reactive oxygen species production and cytochrome c release, thereby allowing cell survival. However, a maladaptive response could enhance fluoride-induced toxicity. The present review gives a brief account of fluoride-induced mitochondrial alterations on soft and hard tissues, including liver, reproductive organs, heart, brain, lung, kidney, bone, and tooth.
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Affiliation(s)
- Sabino Hazael Avila-Rojas
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Departamento de Toxicología (CINVESTAV-IPN), Av. IPN No. 2508 Col., San Pedro Zacatenco, México CP 07360, Mexico.
| | | | - Marco Antonio Sanchez-Guerra
- Department of Developmental Neurobiology, National Institute of Perinatology, Montes Urales 800, Lomas Virreyes, Mexico 1100, Mexico.
| | - Olivier Christophe Barbier
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional. Departamento de Toxicología (CINVESTAV-IPN), Av. IPN No. 2508 Col., San Pedro Zacatenco, México CP 07360, Mexico.
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7
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Castiblanco-Rubio GA, Muñoz-Rocha TV, Téllez-Rojo MM, Ettinger AS, Mercado-García A, Peterson KE, Hu H, Cantoral A, Martínez-Mier EA. Dietary Influences on Urinary Fluoride over the Course of Pregnancy and at One-Year Postpartum. Biol Trace Elem Res 2022; 200:1568-1579. [PMID: 34176079 DOI: 10.1007/s12011-021-02799-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/17/2021] [Indexed: 10/21/2022]
Abstract
Dietary factors are known to influence urinary fluoride (UF) levels in nonpregnant people. Maternal UF is used as a biomarker of fluoride exposure; however, dietary influences on UF during pregnancy are unknown. We compared UF levels and assessed the associations between UF and five select dietary influences in pregnancy vs. one-year postpartum: dietary fluoride (F), calcium intake from diet (Ca-diet), calcium intake from supplements (Ca-sup), dietary acid load (AL), and table salt use (TS) in 421 women exposed to fluoridated salt in the Mexican diet. Spot UF (mg/L) was measured by microdiffusion/fluoride-specific electrode and dilution-corrected with specific gravity (SG). Dietary variables were estimated from a validated Food Frequency Questionnaire. Comparisons among UF in pregnancy vs. one-year postpartum were performed with non-parametric tests. Associations between dietary variables and UF were assessed using random effect models (for pregnancy) and linear regression (for one-year postpartum). SG-corrected UF (median, range) during pregnancy (0.77, 0.01-4.73 mg/L) did not significantly differ from one-year postpartum (0.75, 0.15-2.62 mg/L) but did increase every 10 gestational weeks, β = 0.05 (CI: 0.00-0.10). Different dietary influences on UF were identified at each state. Although Ca-diet and AL were not associated with UF in either state, Ca-sup decreased UF only during pregnancy, β = - 0.012 mg/L (CI: - 0.023-0.00). Reporting TS use was associated with 12% increase in UF only at one-year postpartum (p = 0.026). These results suggest different dietary influences on UF in the pregnant state, which need consideration when using UF as a biomarker of fluoride exposure.
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Affiliation(s)
- Gina A Castiblanco-Rubio
- Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, 415 Lansing St, Indianapolis, IN, 46202, USA.
| | - Teresa V Muñoz-Rocha
- Center for Nutrition and Health Research, Instituto Nacional de Salud Pública de México (INSP), Cuernavaca, Morelos, México
| | - Martha M Téllez-Rojo
- Center for Nutrition and Health Research, Instituto Nacional de Salud Pública de México (INSP), Cuernavaca, Morelos, México
| | - Adrienne S Ettinger
- Rutgers Biomedical and Health Sciences, Rutgers University, New Brunswick, NJ, USA
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Adriana Mercado-García
- Center for Nutrition and Health Research, Instituto Nacional de Salud Pública de México (INSP), Cuernavaca, Morelos, México
| | - Karen E Peterson
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Howard Hu
- Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - E Angeles Martínez-Mier
- Department of Cariology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, 415 Lansing St, Indianapolis, IN, 46202, USA
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Xie X, Wan Y, Zhu B, Liu Q, Zhu K, Jiang Q, Feng Y, Xiao P, Wu X, Zhang J, Meng H, Song R. Association between urinary dialkylphosphate metabolites and dyslexia among children from three cities of China: The READ program. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 814:151852. [PMID: 34826485 DOI: 10.1016/j.scitotenv.2021.151852] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/28/2021] [Accepted: 11/17/2021] [Indexed: 06/13/2023]
Abstract
Exposure to organophosphate (OP) insecticides has been found to be related to neurodevelopmental disorders in children. However, no study has examined the association between OP insecticide exposure and the risk of dyslexia among children. We aimed to explore the association between OP insecticide exposure, indicated by urinary dialkylphosphate metabolites (DAPs), and the risk of dyslexia among Chinese Han children from three cities. A total of 845 children (422 dyslexics and 423 non-dyslexics) from Tongji Reading Environment and Dyslexia research program were included in the current case-control study. We measured six DAPs in urine samples, collected from November 2017 to December 2020. Logistic regression models were used to estimate odds ratios (ORs) for the association between DAPs and dyslexia risk, adjusting for potential confounders. The detection frequencies of DAPs were above 97.5%, except for diethyldithiophosphate and dimethyldithiophosphate. Diethyl phosphate metabolites (DEs) were significantly associated with the risk of dyslexia. Compared with the lowest quartile, the adjusted ORs of dyslexia risk for the highest quartile of urinary diethylthiophosphate (DETP) and diethylphosphate (DEP) were 1.82 (1.04, 3.20) and 1.85 (1.08, 3.17), respectively. In addition, the adjusted ORs for dyslexia per 10-fold of urinary DEP, DETP, and ∑DEs concentration were 1.87 (1.12, 3.13), 1.55 (1.03, 2.35), and 1.91 (1.13, 3.21), respectively. Analyses stratified by gender indicated that such associations were more significant among boys. This study suggested that exposure to OP insecticides may be related to dyslexia among Chinese Han children from the three studied cities. However, our results should be interpreted with caution because of the case-control design and the fact that only one-spot urine sample was collected from the children. More studies with children living in China are necessary concerning the relatively high levels of urinary OP metabolites in our study.
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Affiliation(s)
- Xinyan Xie
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanjian Wan
- Institute of Environmental Health, Wuhan Centers for Disease Control and Prevention, Wuhan, China.
| | - Bing Zhu
- Hangzhou Center for Disease Control and Prevention, Hangzhou, China
| | - Qi Liu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kaiheng Zhu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qi Jiang
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yanan Feng
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pei Xiao
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoqian Wu
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiajia Zhang
- Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, United States
| | - Heng Meng
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ranran Song
- Department of Maternal and Child Health and MOE (Ministry of Education) Key Lab of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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Saylor C, Malin AJ, Tamayo-Ortiz M, Cantoral A, Amarasiriwardena C, Estrada-Gutierrez G, Tolentino MC, Pantic I, Wright RO, Tellez-Rojo MM, Sanders AP. Early childhood fluoride exposure and preadolescent kidney function. ENVIRONMENTAL RESEARCH 2022; 204:112014. [PMID: 34506780 PMCID: PMC11071127 DOI: 10.1016/j.envres.2021.112014] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Early-life renal maturation is susceptible to nephrotoxic environmental chemicals. Given the widespread consumption of fluoride and the global obesity epidemic, our main aim was to determine whether childhood fluoride exposure adversely affects kidney function in preadolescence, and if adiposity status modifies this association. METHODS Our study included 438 children from the PROGRESS cohort. Urinary fluoride (uF) was assessed at age 4 by diffusion analysis; outcomes studied included estimated glomerular filtration rate (eGFR), blood urea nitrogen (BUN), selected kidney proteins and blood pressure measured at age 8-12 years. We modeled the relationship between uF and outcomes, and adjusted for body mass index (BMI), age, sex, and socioeconomic status. RESULTS The median uF concentration was 0.67 μg/mL. We observed null associations between 4-year uF and preadolescent eGFR, although effect estimates were in the expected inverse direction. A single unit increase in ln-transformed uF was associated with a 2.2 mL/min decrease in cystatin C-based eGFR (95% CI: 5.8, 1.4; p = 0.23). We observed no evidence of sex-specific effects or effect modification by BMI status. Although uF was not associated with BMI, among children with obesity, we observed an inverse association (β: 4.8; 95% CI: 10.2, 0.6; p = 0.08) between uF and eGFR. CONCLUSIONS Low-level fluoride exposure in early childhood was not associated with renal function in preadolescence. However, given the adverse outcomes of chronic fluoride consumption it is possible that the preadolescent age was too young to observe any effects. Longitudinal follow-up in this cohort and others is an important next step.
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Affiliation(s)
- Charles Saylor
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ashley J Malin
- Department of Population and Public Health Sciences, Keck School of Medicine of USC, 2001 N Soto St., Los Angeles, CA, 90032, USA.
| | - Marcela Tamayo-Ortiz
- Occupational Health Research Unit, Mexican Social Security Institute, Mexico City, Mexico.
| | - Alejandra Cantoral
- Iberoamerican University -Mexico City, Department of Health, Mexico City, Mexico
| | - Chitra Amarasiriwardena
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - Mari Cruz Tolentino
- Department of Nutrition, National Institute of Perinatology, Mexico City, Mexico
| | - Ivan Pantic
- Department of Developmental Neurobiology, National Institute of Perinatology, Mexico City, Mexico
| | - 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
| | - Martha M Tellez-Rojo
- Occupational Health Research Unit, Mexican Social Security Institute, Mexico City, Mexico
| | - Alison P Sanders
- Department of Environmental and Occupational Health, University of Pittsburgh, USA.
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10
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Dietary fluoride intake during pregnancy and neurodevelopment in toddlers: A prospective study in the progress cohort. Neurotoxicology 2021; 87:86-93. [PMID: 34478773 PMCID: PMC8595627 DOI: 10.1016/j.neuro.2021.08.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/03/2021] [Accepted: 08/28/2021] [Indexed: 12/21/2022]
Abstract
Foods and beverages provide a source of fluoride exposure in Mexico. While high fluoride concentrations are neurotoxic, recent research suggests that exposures within the optimal range may also pose a risk to the developing brain. This prospective study examined whether dietary fluoride intake during pregnancy is associated with toddlers' neurodevelopment in 103 mother-child pairs from the PROGRESS cohort in Mexico City. Food and beverage fluoride intake was assessed in trimesters 2 and 3 using a food frequency questionnaire and Mexican tables of fluoride content. We used the Bayley-III to evaluate cognitive, motor, and language outcomes at 12 and 24 months of age. Adjusted linear regression models were generated for each neurodevelopment assessment time point (12 and 24 months). Mixed-effects models were used to consider a repeated measurement approach. Interactions between maternal fluoride intake and child sex on neurodevelopmental outcomes were tested. Median (IQR) dietary fluoride intake during pregnancy was 1.01 mg/d (0.73, 1.32). Maternal fluoride intake was not associated with cognitive, language, or motor outcomes collapsing across boys and girls. However, child sex modified the association between maternal fluoride intake and cognitive outcome (p interaction term = 0.06). A 0.5 mg/day increase in overall dietary fluoride intake was associated with a 3.50-point lower cognitive outcome in 24-month old boys (95 % CI: -6.58, -0.42); there was no statistical association with girls (β = 0.07, 95 % CI: -2.37, 2.51), nor on the cognitive outcome at 12-months of age. Averaging across the 12- and 24-month cognitive outcomes using mixed-effects models revealed a similar association: a 0.5 mg/day increase in overall dietary fluoride intake was associated with a 3.46-point lower cognitive outcome in boys (95 % CI: -6.23, -0.70). These findings suggest that the development of nonverbal abilities in males may be more vulnerable to prenatal fluoride exposure than language or motor abilities, even at levels within the recommended intake range.
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11
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Farías P, Estevez-García JA, Onofre-Pardo EN, Pérez-Humara ML, Rojas-Lima E, Álamo-Hernández U, Rocha-Amador DO. Fluoride Exposure through Different Drinking Water Sources in a Contaminated Basin in Guanajuato, Mexico: A Deterministic Human Health Risk Assessment. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182111490. [PMID: 34770007 PMCID: PMC8583120 DOI: 10.3390/ijerph182111490] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/06/2021] [Accepted: 10/13/2021] [Indexed: 01/18/2023]
Abstract
Water fluoride levels above the World Health Organization’s guideline (1.5 mg/L), common in overexploited aquifers, represent a health hazard. Our objective was to assess the health risks posed by exposure to fluoride in different drinking water sources in a contaminated basin in Mexico. Fluoride was measured in mutual drinking water sources and in the urine of 39 children and women. Risks were estimated through hazard quotient (HQ) by drinking water source. Dental fluorosis was assessed in the children. Mean fluoride water concentrations (mg/L) were: well, 4.2; waterhole, 2.7; bottled, 2.1; rainwater, 0.4. The mean urinary fluoride concentrations (specific gravity adjusted) were 2.1 mg/L and 3.2 mg/L in children and women, respectively. Our multiple linear regression model showed children’s urinary fluoride concentrations increased 0.96 mg/L for every 1 mg/L increase in water fluoride (p < 0.001). Dental fluorosis was diagnosed in 82% of the children, and their HQ according to drinking water source was: well, 1.5; waterhole, 1.1; bottled, 0.8; harvested rainwater, 0.3. The pervasive dental fluorosis indicates a toxic past fluoride exposure; urinary fluoride levels and HQs indicate high exposure and current health risks for most children. Drinking harvested rainwater will likely prevent most of the local fluoride exposure.
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Affiliation(s)
- Paulina Farías
- Instituto Nacional de Salud Pública, Universidad No. 655, Colonia Santa María Ahuacatitlán, Cuernavaca 62100, Mexico; (J.A.E.-G.); (E.N.O.-P.); (M.L.P.-H.); (E.R.-L.); (U.Á.-H.)
- Correspondence:
| | - Jesús Alejandro Estevez-García
- Instituto Nacional de Salud Pública, Universidad No. 655, Colonia Santa María Ahuacatitlán, Cuernavaca 62100, Mexico; (J.A.E.-G.); (E.N.O.-P.); (M.L.P.-H.); (E.R.-L.); (U.Á.-H.)
| | - Erika Noelia Onofre-Pardo
- Instituto Nacional de Salud Pública, Universidad No. 655, Colonia Santa María Ahuacatitlán, Cuernavaca 62100, Mexico; (J.A.E.-G.); (E.N.O.-P.); (M.L.P.-H.); (E.R.-L.); (U.Á.-H.)
| | - María Luisa Pérez-Humara
- Instituto Nacional de Salud Pública, Universidad No. 655, Colonia Santa María Ahuacatitlán, Cuernavaca 62100, Mexico; (J.A.E.-G.); (E.N.O.-P.); (M.L.P.-H.); (E.R.-L.); (U.Á.-H.)
| | - Elodia Rojas-Lima
- Instituto Nacional de Salud Pública, Universidad No. 655, Colonia Santa María Ahuacatitlán, Cuernavaca 62100, Mexico; (J.A.E.-G.); (E.N.O.-P.); (M.L.P.-H.); (E.R.-L.); (U.Á.-H.)
| | - Urinda Álamo-Hernández
- Instituto Nacional de Salud Pública, Universidad No. 655, Colonia Santa María Ahuacatitlán, Cuernavaca 62100, Mexico; (J.A.E.-G.); (E.N.O.-P.); (M.L.P.-H.); (E.R.-L.); (U.Á.-H.)
| | - Diana Olivia Rocha-Amador
- Departamento de Farmacia, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Guanajuato 36050, Mexico;
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12
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Farmus L, Till C, Green R, Hornung R, Martinez Mier EA, Ayotte P, Muckle G, Lanphear BP, Flora DB. Critical windows of fluoride neurotoxicity in Canadian children. ENVIRONMENTAL RESEARCH 2021; 200:111315. [PMID: 34051202 PMCID: PMC9884092 DOI: 10.1016/j.envres.2021.111315] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/28/2021] [Accepted: 05/07/2021] [Indexed: 05/08/2023]
Abstract
BACKGROUND Fluoride has been associated with IQ deficits during early brain development, but the period in which children are most sensitive is unknown. OBJECTIVE We assessed effects of fluoride on IQ scores across prenatal and postnatal exposure windows. METHODS We used repeated exposures from 596 mother-child pairs in the Maternal-Infant Research on Environmental Chemicals pregnancy and birth cohort. Fluoride was measured in urine (mg/L) collected from women during pregnancy and in their children between 1.9 and 4.4 years; urinary fluoride was adjusted for specific gravity. We estimated infant fluoride exposure (mg/day) using water fluoride concentration and duration of formula-feeding over the first year of life. Intelligence was assessed at 3-4 years using the Wechsler Preschool and Primary Scale of Intelligence-III. We used generalized estimating equations to examine the associations between fluoride exposures and IQ, adjusting for covariates. We report results based on standardized exposures given their varying units of measurement. RESULTS The association between fluoride and performance IQ (PIQ) significantly differed across prenatal, infancy, and childhood exposure windows collapsing across child sex (p = .001). The strongest association between fluoride and PIQ was during the prenatal window, B = -2.36, 95% CI: -3.63, -1.08; the association was also significant during infancy, B = -2.11, 95% CI: -3.45, -0.76, but weaker in childhood, B = -1.51, 95% CI: -2.90, -0.12. Within sex, the association between fluoride and PIQ significantly differed across the three exposure windows (boys: p = .01; girls: p = .01); among boys, the strongest association was during the prenatal window, B = -3.01, 95% CI: -4.60, -1.42, whereas among girls, the strongest association was during infancy, B = -2.71, 95% CI: -4.59, -0.83. Full-scale IQ estimates were weaker than PIQ estimates for every window. Fluoride was not significantly associated with Verbal IQ across any exposure window. CONCLUSION Associations between fluoride exposure and PIQ differed based on timing of exposure. The prenatal window may be critical for boys, whereas infancy may be a critical window for girls.
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Affiliation(s)
- Linda Farmus
- Faculty of Health, York University, Ontario, Canada
| | | | - Rivka Green
- Faculty of Health, York University, Ontario, Canada
| | - Richard Hornung
- Pediatrics and Environmental Health, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - E Angeles Martinez Mier
- Department of Cardiology, Operative Dentistry and Dental Public Health, Indiana University School of Dentistry, Indiana, USA
| | - Pierre Ayotte
- Centre de Recherche Du CHU de Québec, Université Laval, Québec, Canada; Department of Social and Preventive Medicine, Laval University, Quebec, Canada
| | - Gina Muckle
- Centre de Recherche Du CHU de Québec, Université Laval, Québec, Canada; School of Psychology, Laval University, Quebec, Canada
| | - Bruce P Lanphear
- Faculty of Health Sciences, Simon Fraser University, British Columbia, Canada; Child & Family Research Institute, BC Children's Hospital, University of British Columbia, British Columbia, Canada
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13
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Riddell JK, Malin AJ, McCague H, Flora DB, Till C. Urinary Fluoride Levels among Canadians with and without Community Water Fluoridation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:6203. [PMID: 34201160 PMCID: PMC8226595 DOI: 10.3390/ijerph18126203] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/04/2021] [Accepted: 06/06/2021] [Indexed: 11/17/2022]
Abstract
Drinking water is a major source of dietary fluoride intake in communities with water fluoridation. We examined the association between urinary fluoride adjusted for specific gravity (UFSG) and tap water fluoride levels, by age and sex, among individuals living in Canada. Participants included 1629 individuals aged 3 to 79 years from Cycle 3 (2012-2013) of the Canadian Health Measures Survey. We used multiple linear regression to estimate unique associations of tap water fluoride levels, age, sex, ethnicity, body mass index (BMI), use of fluoride-containing dental products, smoking in the home, and tea consumption with UFSG. UFSG concentration was significantly higher among participants who received fluoridated drinking water (mean = 1.06 mg/L, standard deviation = 0.83) than among those who did not (M = 0.58 mg/L, SD = 0.47), p < 0.01. UFSG increased over adulthood (ages 19 to 79). Higher UFSG concentration was associated with being female, tea drinking, and smoking in the home. In conclusion, community water fluoridation is a major source of contemporary fluoride exposure for Canadians. Lifestyle factors including tea consumption, as well as demographic variables such as age and sex, also predict urinary fluoride level, and are therefore important factors when interpreting population-based fluoride biomonitoring data.
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Affiliation(s)
- Julia K. Riddell
- Department of Clinical Health Psychology, University of Manitoba, Winnipeg, MB N3E 3N4, Canada
| | - Ashley J. Malin
- Department of Preventive Medicine, Keck School of Medicine of USC, Los Angeles, CA 90032, USA;
| | - Hugh McCague
- Institute for Social Research, York University, Toronto, ON M3J 1P3, Canada; (H.M.); (D.B.F.)
| | - David B. Flora
- Institute for Social Research, York University, Toronto, ON M3J 1P3, Canada; (H.M.); (D.B.F.)
- Faculty of Health, York University, Toronto, ON M3J 1P3, Canada;
| | - Christine Till
- Faculty of Health, York University, Toronto, ON M3J 1P3, Canada;
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