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Kong H, He Z, Li H, Xing D, Lin J. The Association between Fluoride and Bone Mineral Density in US Children and Adolescents: A Pilot Study. Nutrients 2024; 16:2948. [PMID: 39275266 PMCID: PMC11397378 DOI: 10.3390/nu16172948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/28/2024] [Accepted: 08/31/2024] [Indexed: 09/16/2024] Open
Abstract
The aim of this study was to examine the association between fluoride exposure and bone mineral density (BMD) in children and adolescents. We used data from the National Health and Nutrition Examination Survey (NHANES) 2015-2016. The fluoride concentrations in the water samples, plasma samples, and urine samples were measured electrometrically using an ion-specific electrode. Total body less head BMD (TBLH BMD) was measured using dual-energy X-ray absorptiometry (DXA). Weighted generalized linear regression models and restricted cubic splines (RCS) regression models were used to analyze the relationships between the three types of fluoride exposure and TBLH BMD. We performed subgroup analyses stratified by sex. A total of 1413 US children and adolescents were included in our study. In our linear regression models, we found inverse associations between fluoride concentrations in water and plasma and TBLH BMD. Additionally, we discovered a non-linear association between fluoride concentrations in water and plasma and TBLH BMD. No significant association or non-linear relationship was found between urine fluoride levels and TBLH BMD. This nationally representative sample study provides valuable insight into the intricate connection between fluoride exposure and skeletal health in children and adolescents.
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Affiliation(s)
- Haichen Kong
- Arthritis Clinic and Research Center, Peking University People's Hospital, Peking University, Beijing 100044, China
| | - Zihao He
- Arthritis Clinic and Research Center, Peking University People's Hospital, Peking University, Beijing 100044, China
| | - Hui Li
- Arthritis Clinic and Research Center, Peking University People's Hospital, Peking University, Beijing 100044, China
| | - Dan Xing
- Arthritis Clinic and Research Center, Peking University People's Hospital, Peking University, Beijing 100044, China
| | - Jianhao Lin
- Arthritis Clinic and Research Center, Peking University People's Hospital, Peking University, Beijing 100044, China
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Wong MCM, Zhang R, Luo BW, Glenny AM, Worthington HV, Lo ECM. Topical fluoride as a cause of dental fluorosis in children. Cochrane Database Syst Rev 2024; 6:CD007693. [PMID: 38899538 PMCID: PMC11187792 DOI: 10.1002/14651858.cd007693.pub3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
BACKGROUND This is an update of a review first published in 2010. Use of topical fluoride has become more common over time. Excessive fluoride consumption from topical fluorides in young children could potentially lead to dental fluorosis in permanent teeth. OBJECTIVES To describe the relationship between the use of topical fluorides in young children and the risk of developing dental fluorosis in permanent teeth. SEARCH METHODS We carried out electronic searches of the Cochrane Oral Health Trials Register, CENTRAL, MEDLINE, Embase, three other databases, and two trials registers. We searched the reference lists of relevant articles. The latest search date was 28 July 2022. SELECTION CRITERIA We included randomized controlled trials (RCTs), quasi-RCTs, cohort studies, case-control studies, and cross-sectional surveys comparing fluoride toothpaste, mouth rinses, gels, foams, paint-on solutions, and varnishes to a different fluoride therapy, placebo, or no intervention. Upon the introduction of topical fluorides, the target population was children under six years of age. DATA COLLECTION AND ANALYSIS We used standard methodological procedures expected by Cochrane and used GRADE to assess the certainty of the evidence. The primary outcome measure was the percentage prevalence of fluorosis in the permanent teeth. Two authors extracted data from all included studies. In cases where both adjusted and unadjusted risk ratios or odds ratios were reported, we used the adjusted value in the meta-analysis. MAIN RESULTS We included 43 studies: three RCTs, four cohort studies, 10 case-control studies, and 26 cross-sectional surveys. We judged all three RCTs, one cohort study, one case-control study, and six cross-sectional studies to have some concerns for risk of bias. We judged all other observational studies to be at high risk of bias. We grouped the studies into five comparisons. Comparison 1. Age at which children started toothbrushing with fluoride toothpaste Two cohort studies (260 children) provided very uncertain evidence regarding the association between children starting to use fluoride toothpaste for brushing at or before 12 months versus after 12 months and the development of fluorosis (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.81 to 1.18; very low-certainty evidence). Similarly, evidence from one cohort study (3939 children) and two cross-sectional studies (1484 children) provided very uncertain evidence regarding the association between children starting to use fluoride toothpaste for brushing before or after the age of 24 months (RR 0.83, 95% CI 0.61 to 1.13; very low-certainty evidence) or before or after four years (odds ratio (OR) 1.60, 95% CI 0.77 to 3.35; very low-certainty evidence), respectively. Comparison 2. Frequency of toothbrushing with fluoride toothpaste Two case-control studies (258 children) provided very uncertain evidence regarding the association between children brushing less than twice per day versus twice or more per day and the development of fluorosis (OR 1.63, 95% CI 0.81 to 3.28; very low-certainty evidence). Two cross-sectional surveys (1693 children) demonstrated that brushing less than once per day versus once or more per day may be associated with a decrease in the development of fluorosis in children (OR 0.62, 95% CI 0.53 to 0.74; low-certainty evidence). Comparison 3. Amount of fluoride toothpaste used for toothbrushing Two case-control studies (258 children) provided very uncertain evidence regarding the association between children using less than half a brush of toothpaste, versus half or more of the brush, and the development of fluorosis (OR 0.77, 95% CI 0.41 to 1.46; very low-certainty evidence). The evidence from cross-sectional surveys was also very uncertain (OR 0.92, 95% CI 0.66 to 1.28; 3 studies, 2037 children; very low-certainty evidence). Comparison 4. Fluoride concentration in toothpaste There was evidence from two RCTs (1968 children) that lower fluoride concentration in the toothpaste used by children under six years of age likely reduces the risk of developing fluorosis: 550 parts per million (ppm) fluoride versus 1000 ppm (RR 0.75, 95% CI 0.57 to 0.99; moderate-certainty evidence); 440 ppm fluoride versus 1450 ppm (RR 0.72, 95% CI 0.58 to 0.89; moderate-certainty evidence). The age at which the toothbrushing commenced was 24 months and 12 months, respectively. Two case-control studies (258 children) provided very uncertain evidence regarding the association between fluoride concentrations under 1000 ppm, versus concentrations of 1000 ppm or above, and the development of fluorosis (OR 0.89, 95% CI 0.52 to 1.52; very low-certainty evidence). Comparison 5. Age at which topical fluoride varnish was applied There was evidence from one RCT (123 children) that there may be little to no difference between a fluoride varnish application before four years, versus no application, and the development of fluorosis (RR 0.77, 95% CI 0.45 to 1.31; low-certainty evidence). There was low-certainty evidence from two cross-sectional surveys (982 children) that the application of topical fluoride varnish before four years of age may be associated with the development of fluorosis in children (OR 2.18, 95% CI 1.46 to 3.25). AUTHORS' CONCLUSIONS Most evidence identified mild fluorosis as a potential adverse outcome of using topical fluoride at an early age. There is low- to very low-certainty and inconclusive evidence on the risk of having fluorosis in permanent teeth for: when a child starts receiving topical fluoride varnish application; toothbrushing with fluoride toothpaste; the amount of toothpaste used by the child; and the frequency of toothbrushing. Moderate-certainty evidence from RCTs showed that children who brushed with 1000 ppm or more fluoride toothpaste from one to two years of age until five to six years of age probably had an increased chance of developing dental fluorosis in permanent teeth. It is unethical to propose new RCTs to assess the development of dental fluorosis. However, future RCTs focusing on dental caries prevention could record children's exposure to topical fluoride sources in early life and evaluate the dental fluorosis in their permanent teeth as a long-term outcome. In the absence of these studies and methods, further research in this area will come from observational studies. Attention needs to be given to the choice of study design, bearing in mind that prospective controlled studies will be less susceptible to bias than retrospective and uncontrolled studies.
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Affiliation(s)
- May Chun Mei Wong
- Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Rui Zhang
- Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Bella Weijia Luo
- Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Anne-Marie Glenny
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Helen V Worthington
- Cochrane Oral Health, Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Edward Chin Man Lo
- Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
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Malin AJ, Hu H, Martínez-Mier EA, Eckel SP, Farzan SF, Howe CG, Funk W, Meeker JD, Habre R, Bastain TM, Breton CV. Urinary fluoride levels and metal co-exposures among pregnant women in Los Angeles, California. Environ Health 2023; 22:74. [PMID: 37880740 PMCID: PMC10601173 DOI: 10.1186/s12940-023-01026-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 10/13/2023] [Indexed: 10/27/2023]
Abstract
BACKGROUND Fluoride is ubiquitous in the United States (US); however, data on biomarkers and patterns of fluoride exposure among US pregnant women are scarce. We examined specific gravity adjusted maternal urinary fluoride (MUFsg) in relation to sociodemographic variables and metal co-exposures among pregnant women in Los Angeles, California. METHODS Participants were from the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) cohort. There were 293 and 490 women with MUFsg measured during first and third trimesters, respectively. An intra-class correlation coefficient examined consistency of MUFsg between trimesters. Kruskal-Wallis and Mann-Whitney U tests examined associations of MUFsg with sociodemographic variables. Covariate adjusted linear regression examined associations of MUFsg with blood metals and specific gravity adjusted urine metals among a subsample of participants within and between trimesters. A False Discovery Rate (FDR) correction accounted for multiple comparisons. RESULTS Median (IQR) MUFsg was 0.65 (0.5) mg/L and 0.8 (0.59) mg/L, during trimesters one and three respectively. During both trimesters, MUFsg was higher among older participants, those with higher income, and White, non-Hispanic participants than Hispanic participants. MUFsg was also higher for White, non-Hispanic participants than for Black, non-Hispanic participants in trimester three, and for those with graduate training in trimester one. MUFsg was negatively associated with blood mercury in trimester one and positively associated with blood lead in trimester three. MUFsg was positively associated with various urinary metals, including antimony, barium, cadmium, cobalt, copper, lead, nickel, tin, and zinc in trimesters one and/or three. CONCLUSIONS MUFsg levels observed were comparable to those found in pregnant women in Mexico and Canada that have been associated with poorer neurodevelopmental outcomes. Lower urinary fluoride levels among Hispanic and non-Hispanic Black participants in MADRES compared to non-Hispanic White participants may reflect lower tap water consumption or lower fluoride exposure from other sources. Additional research is needed to examine whether MUFsg levels observed among pregnant women in the US are associated with neurodevelopmental outcomes.
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Affiliation(s)
- Ashley J Malin
- Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, 2004 Mowry Rd, Gainesville, 32603, USA.
| | - Howard Hu
- Department of Population and Public Health Sciences, Keck School of Medicine of University of Southern California, 1845 N Soto Street, Los Angeles, CA, 90089-9239, USA
| | - E Angeles Martínez-Mier
- Department of Cariology, Operative Dentistry and Dental Public Health, School of Dentistry, Indiana University, 1121 W. Michigan St., Indianapolis, IN, 46202-2876, USA
| | - Sandrah P Eckel
- Department of Population and Public Health Sciences, Keck School of Medicine of University of Southern California, 1845 N Soto Street, Los Angeles, CA, 90089-9239, USA
| | - Shohreh F Farzan
- Department of Population and Public Health Sciences, Keck School of Medicine of University of Southern California, 1845 N Soto Street, Los Angeles, CA, 90089-9239, USA
| | - Caitlin G Howe
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, 1 Medical Center Drive, Williamson Translational Research Building, 7th Floor, Lebanon, NH, 03756, USA
| | - William Funk
- Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, 680 N Lake Shore Dr Ste 1400, Chicago, IL, 60611, USA
| | - John D Meeker
- Department of Environmental Health Sciences, University of Michigan School of Public Health, 1420 Washington Hts, Ann Arbor, MI, 48109, USA
| | - Rima Habre
- Department of Population and Public Health Sciences, Keck School of Medicine of University of Southern California, 1845 N Soto Street, Los Angeles, CA, 90089-9239, USA
| | - Theresa M Bastain
- Department of Population and Public Health Sciences, Keck School of Medicine of University of Southern California, 1845 N Soto Street, Los Angeles, CA, 90089-9239, USA
| | - Carrie V Breton
- Department of Population and Public Health Sciences, Keck School of Medicine of University of Southern California, 1845 N Soto Street, Los Angeles, CA, 90089-9239, 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: 10] [Impact Index Per Article: 10.0] [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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Balasubramanian S, Perumal E. A systematic review on fluoride-induced epigenetic toxicity in mammals. Crit Rev Toxicol 2022; 52:449-468. [PMID: 36422650 DOI: 10.1080/10408444.2022.2122771] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Fluoride, one of the global groundwater contaminants, is ubiquitous in our day-to-day life from various natural and anthropogenic sources. Numerous in vitro, in vivo, and epidemiological studies are conducted to understand the effect of fluoride on biological systems. A low concentration of fluoride is reported to increase oral health, whereas chronic exposure to higher concentrations causes fluoride toxicity (fluorosis). It includes dental fluorosis, skeletal fluorosis, and fluoride toxicity in soft tissues. The mechanism of fluoride toxicity has been reviewed extensively. However, epigenetic regulation in fluoride toxicity has not been reviewed. This systematic review summarizes the current knowledge regarding fluoride-induced epigenetic toxicity in the in vitro, in vivo, and epidemiological studies in mammalian systems. We examined four databases for the association between epigenetics and fluoride exposure. Out of 932 articles (as of 31 March 2022), 39 met our inclusion criteria. Most of the studies focused on different genes, and overall, preliminary evidence for epigenetic regulation of fluoride toxicity was identified. We further highlight the need for epigenome studies rather than candidate genes and provide recommendations for future research. Our results indicate a correlation between fluoride exposure and epigenetic processes. Further studies are warranted to elucidate and confirm the mechanism of epigenetic alterations mediated fluoride toxicity.
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Affiliation(s)
| | - Ekambaram Perumal
- Molecular Toxicology Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, India
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Saad H, Escoube R, Babajko S, Houari S. Fluoride Intake Through Dental Care Products: A Systematic Review. FRONTIERS IN ORAL HEALTH 2022; 3:916372. [PMID: 35757442 PMCID: PMC9231728 DOI: 10.3389/froh.2022.916372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 05/04/2022] [Indexed: 11/24/2022] Open
Abstract
Fluoride (F) is added to many dental care products as well as in drinking water to prevent dental decay. However, recent data associating exposure to F with some developmental defects with consequences in many organs raise concerns about its daily use for dental care. This systematic review aimed to evaluate the contribution of dental care products with regard to overall F intake through drinking water and diet with measurements of F excretion in urine used as a suitable biomarker. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using keywords related to chronic exposure to F in the human population with measurements of F levels in body fluids, 1,273 papers published between 1995 and 2021 were screened, and 28 papers were finally included for data extraction concerning daily F intake. The contribution of dental care products, essentially by toothbrushing with kinds of toothpaste containing F, was 38% in the mean regardless of the F concentrations in drinking water. There was no correlation between F intake through toothpaste and age, nor with F levels in water ranging from 0.3 to 1.5 mg/L. There was no correlation between F intake and urinary F excretion levels despite an increase in its content in urine within hours following exposure to dental care products (toothpastes, varnishes, or other dental care products). The consequences of exposure to F on health are discussed in the recent context of its suspected toxicity reported in the literature. The conclusions of the review aim to provide objective messages to patients and dental professionals worried about the use of F-containing materials or products to prevent initial caries or hypomineralized enamel lesions, especially for young children.
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Affiliation(s)
- Hanan Saad
- Laboratory of Molecular Oral Physiopathology, Centre de Recherche des Cordeliers, INSERM, Université Paris Cité, Sorbonne Université, Paris, France
- AP-HP, Dental Medicine Department, Pitié-Salpétrière Hospital, GHN-Université Paris Cité, Paris, France
| | - Raphaëlle Escoube
- Laboratoire de Géologie de Lyon, UM R5276, CNRS, Université Lyon 1, École Normale Supérieure de Lyon 46, Lyon, France
| | - Sylvie Babajko
- Laboratory of Molecular Oral Physiopathology, Centre de Recherche des Cordeliers, INSERM, Université Paris Cité, Sorbonne Université, Paris, France
- *Correspondence: Sylvie Babajko
| | - Sophia Houari
- Laboratory of Molecular Oral Physiopathology, Centre de Recherche des Cordeliers, INSERM, Université Paris Cité, Sorbonne Université, Paris, France
- AP-HP, Dental Medicine Department, Pitié-Salpétrière Hospital, GHN-Université Paris Cité, Paris, France
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Idowu OS, Duckworth RM, Valentine RA, Zohoori FV. Biomarkers for the Assessment of Exposure to Fluoride in Adults. Caries Res 2021; 55:292-300. [PMID: 34062534 DOI: 10.1159/000516091] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 03/21/2021] [Indexed: 11/19/2022] Open
Abstract
To monitor deficient or excessive intakes of biologically available fluoride (F), various biological samples have been tested for use as biomarkers of human exposure to F. Most such studies have concerned children and often have only involved measurement of F in 1 or 2 types of sample. The present study investigated the relationships of F concentrations in biomarkers of F exposure; including plasma, saliva, hair, finger- and toenails, and daily urinary F excretion (UFE) with the total daily F intake (TDFI) of adults. TDFI was assessed in 60 healthy adults, aged ≥20 years; 31 lived in a low-F water area (LFA, 0.04 mg F/L) and 29 in a high-F water area (HFA, 3.05 mg F/L) of Nigeria. All volunteers provided at least 1 biomarker sample from the above list and completed a questionnaire to evaluate F intake from the diet and toothpaste ingestion. TDFI, UFE and F concentrations of biomarkers were statistically significantly higher in the HFA than in the LFA. There were strong statistically significant positive correlations between TDFI and UFE (ρ = 0.730, p < 0.001); plasma F (ρ = 0.729, p < 0.001); fasting whole saliva F (ρ = 0.653, p < 0.001) and hair F (ρ = 0.603, p < 0.001). The statistically significant positive correlations between TDFI and fingernail F (ρ = 0.502, p < 0.001) and between TDFI and toenail F (ρ = 0.556, p < 0.001) were moderate. In conclusion, this study has indicated the usefulness of 24-h UFE as well as F concentration in plasma, fasting whole saliva and hair as biomarkers of contemporary or sub-chronic F exposure in groups of adults. However, they do not appear to have the necessary sensitivity to predict F exposure in individuals.
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Affiliation(s)
- Oladipo S Idowu
- School of Health and Life Sciences, Teesside University, Middlesbrough Tees Valley, Middlesbrough, United Kingdom
| | - Ralph M Duckworth
- School of Health and Life Sciences, Teesside University, Middlesbrough Tees Valley, Middlesbrough, United Kingdom
| | - Ruth A Valentine
- School of Dental Sciences, Newcastle University, Framlington Place, Newcastle upon Tyne, United Kingdom
| | - Fatemeh V Zohoori
- School of Health and Life Sciences, Teesside University, Middlesbrough Tees Valley, Middlesbrough, United Kingdom
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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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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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10
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Malin AJ, Lesseur C, Busgang SA, Curtin P, Wright RO, Sanders AP. Fluoride exposure and kidney and liver function among adolescents in the United States: NHANES, 2013-2016. ENVIRONMENT INTERNATIONAL 2019; 132:105012. [PMID: 31402058 PMCID: PMC6754771 DOI: 10.1016/j.envint.2019.105012] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/10/2019] [Accepted: 07/11/2019] [Indexed: 05/09/2023]
Abstract
BACKGROUND Hepato- and nephrotoxicity of fluoride have been demonstrated in animals, but few studies have examined potential effects in humans. This population-based study examines the relationship between chronic low-level fluoride exposure and kidney and liver function among United States (U.S.) adolescents. This study aimed to evaluate whether greater fluoride exposure is associated with altered kidney and liver parameters among U.S. youth. METHODS This cross-sectional study utilized data from the National Health and Nutrition Examination Survey (2013-2016). We analyzed data from 1983 and 1742 adolescents who had plasma and water fluoride measures respectively and did not have kidney disease. Fluoride was measured in plasma and household tap water. Kidney parameters included estimated glomerular filtration rate (calculated by the original Schwartz formula), serum uric acid, and the urinary albumin to creatinine ratio. Liver parameters were assessed in serum and included alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, blood urea nitrogen, gamma-glutamyl transferase, and albumin. Survey-weighted linear regression examined relationships between fluoride exposure and kidney and liver parameters after covariate adjustment. A Holm-Bonferroni correction accounted for multiple comparisons. RESULTS The average age of adolescents was 15.4 years. Median water and plasma fluoride concentrations were 0.48 mg/L and 0.33 μmol/L respectively. A 1 μmol/L increase in plasma fluoride was associated with a 10.36 mL/min/1.73 m2 lower estimated glomerular filtration rate (95% CI: -17.50, -3.22; p = 0.05), a 0.29 mg/dL higher serum uric acid concentration (95% CI: 0.09, 0.50; p = 0.05), and a 1.29 mg/dL lower blood urea nitrogen concentration (95%CI: -1.87, -0.70; p < 0.001). A 1 mg/L increase in water fluoride was associated with a 0.93 mg/dL lower blood urea nitrogen concentration (95% CI: -1.44, -0.42; p = 0.007). CONCLUSIONS Fluoride exposure may contribute to complex changes in kidney and liver related parameters among U.S. adolescents. As the study is cross-sectional, reverse causality cannot be ruled out; therefore, altered kidney and/or liver function may impact bodily fluoride absorption and metabolic processes.
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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.
| | - Corina Lesseur
- Department of Environmental Medicine and Public Health, 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
| | - Paul Curtin
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, 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
| | - Alison P Sanders
- 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
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11
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Idowu OS, Azevedo LB, Valentine RA, Swan J, Vasantavada PV, Maguire A, Zohoori FV. The use of urinary fluoride excretion to facilitate monitoring fluoride intake: A systematic scoping review. PLoS One 2019; 14:e0222260. [PMID: 31509581 PMCID: PMC6738609 DOI: 10.1371/journal.pone.0222260] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/25/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND As a recognised effective and economical agent for dental caries prevention, fluoride has been used in many different fluoridation schemes implemented across the world. Considering the narrow 'dose-gap' between the benefit of caries reduction and the risk of dental fluorosis, it is recommended that fluoride intake is monitored by measuring urinary fluoride excretion. The aim of this scoping review is to map the current literature/evidence on fluoride intake and excretion studies in relation to the study population, settings, type of study design, methodology, and analytical approach. METHODS Embase/Ovid, MEDLINE/Ovid, CINAHL/EBSCO, Scopus/Elsevier were searched for relevant articles until April 2018. Studies were included if they reported intake and excretion of fluoride in healthy humans of all age groups. Findings were explored using a narrative synthesis to summarise studies characteristics and outcome measures. RESULTS Removal of duplicates from the originally 2295 identified records yielded 1093 studies of which 206 articles were included. Only 21.6% of the studies were conducted in children (<8-year-olds). Most studies (38.8%) used drinking water concentration as a proxy for fluoride intake, whereas only 11.7% measured fluoride intake from all sources. Of the 72 studies that measured dietary fluoride intake, only 10 reported the validity of the employed dietary assessment method. Only 14 studies validated the urine sample collection methods. No information on the validity of the employed analytical method was reported by the majority (64.6%) of studies. Only a small proportion (8.7%) of the included studies investigated the association between fluoride intake and excretion. CONCLUSION The findings reveal much variability in terms of conducting the studies and reporting the findings, illustrating a high heterogeneity in data collection across settings and populations. Future studies should provide more detail on sampling technique, measurement protocols (including validation), and on clearly defining the relationship between intake and urinary excretion of fluoride.
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Affiliation(s)
- Oladipo S. Idowu
- School of Health and Social Care, Teesside University, Middlesbrough Tees Valley, United Kingdom
- School of Dental Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, United Kingdom
| | - Liane B. Azevedo
- School of Health and Social Care, Teesside University, Middlesbrough Tees Valley, United Kingdom
| | - Ruth A. Valentine
- School of Dental Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, United Kingdom
| | - Josie Swan
- School of Dental Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, United Kingdom
| | - Priyanka V. Vasantavada
- School of Health and Social Care, Teesside University, Middlesbrough Tees Valley, United Kingdom
| | - Anne Maguire
- School of Dental Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, United Kingdom
| | - Fatemeh V. Zohoori
- School of Health and Social Care, Teesside University, Middlesbrough Tees Valley, United Kingdom
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12
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Spencer KF, Limeback H. Blood is thicker than water: Flaws in a National Toxicology Program study. Med Hypotheses 2018; 121:160-163. [DOI: 10.1016/j.mehy.2018.09.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 09/12/2018] [Accepted: 09/14/2018] [Indexed: 02/08/2023]
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13
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Ajiboye A, Dawson D, Fox C. American Association for Dental Research Policy Statement on Community Water Fluoridation. J Dent Res 2018; 97:1293-1296. [DOI: 10.1177/0022034518797274] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- A.S. Ajiboye
- American Association for Dental Research, Alexandria, VA, USA
| | - D.R. Dawson
- College of Dentistry, University of Kentucky, Lexington, KY, USA
| | - C.H. Fox
- American Association for Dental Research, Alexandria, VA, USA
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14
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Arora S, Kumar JV, Moss ME. Does water fluoridation affect the prevalence of enamel fluorosis differently among racial and ethnic groups? J Public Health Dent 2017; 78:95-99. [DOI: 10.1111/jphd.12258] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 09/26/2017] [Accepted: 10/06/2017] [Indexed: 11/28/2022]
Affiliation(s)
| | - Jayanth V. Kumar
- California Department of Public Health, Chronic Disease Control Branch; Sacramento CA USA
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Abstract
Although the association between inflammatory bowel disease (IBD) and oral hygiene has been noticed before, there has been little research on prolonged fluoride exposure as a possible risk factor. In the presented cases, exposure to fluoride seems indirectly associated with higher incidence of IBD. Fluoride toxicology and epidemiology documents frequent unspecific chronic gastrointestinal symptoms and intestinal inflammation. Efflux genes that confer resistance to environmental fluoride may select for IBD associated gut microbiota and therefore be involved in the pathogenesis. Together these multidisciplinary results argue for further investigation on the hypothesis of fluoride as a risk factor for IBD.
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Affiliation(s)
| | - Bjørn Moum
- b Department of Gastroenterology , Oslo University Hospital Ullevaal & University of Oslo , Oslo , Norway
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16
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Martinez-Mier EA, Zandona AF. The impact of gender on caries prevalence and risk assessment. Dent Clin North Am 2013; 57:301-315. [PMID: 23570807 DOI: 10.1016/j.cden.2013.01.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Dental caries remains a common disease worldwide. There is evidence indicating that many caries risk factors provide a gender bias, placing women at a higher caries risk. Generally, dental caries disproportionally affects the poor and racial or ethnic minorities worldwide, with women suffering more from the disease. Differences in access to care as reflected by untreated caries rates also reflect gender disparities. There is a lack of evidence in regard to gender differences and dental caries. Therefore, there is an urgent need to develop the evidence necessary to meet the oral health needs of both women and men worldwide.
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