Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015)

Perrott, Kelly

doi:10.1038/sj.bdj.2017.988

Cited by 7 publications

(6 citation statements)

References 7 publications

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“…Given the state-level exposure assessment and the use of parental reports of ADHD, this ecological study has important weaknesses, although the findings are in agreement with other recent studies. However, the study has been criticized, as inclusion of mean elevation as a covariate apparently abolishes the significance of fluoridation as a predictor [130].…”

Section: Resultsmentioning

confidence: 99%

Developmental fluoride neurotoxicity: an updated review

Grandjean

2019

Environ Health

141

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Background: After the discovery of fluoride as a caries-preventing agent in the mid-twentieth century, fluoridation of community water has become a widespread intervention, sometimes hailed as a mainstay of modern public health. However, this practice results in elevated fluoride intake and has become controversial for two reasons. First, topical fluoride application in the oral cavity appears to be a more direct and appropriate means of preventing caries. Second, systemic fluoride uptake is suspected of causing adverse effects, in particular neurotoxicity during early development. The latter is supported by experimental neurotoxicity findings and toxicokinetic evidence of fluoride passing into the brain. Method: An integrated literature review was conducted on fluoride exposure and intellectual disability, with a main focus on studies on children published subsequent to a meta-analysis from 2012. Results: Fourteen recent cross-sectional studies from endemic areas with naturally high fluoride concentrations in groundwater supported the previous findings of cognitive deficits in children with elevated fluoride exposures. Three recent prospective studies from Mexico and Canada with individual exposure data showed that early-life exposures were negatively associated with children's performance on cognitive tests. Neurotoxicity appeared to be dose-dependent, and tentative benchmark dose calculations suggest that safe exposures are likely to be below currently accepted or recommended fluoride concentrations in drinking water. Conclusion: The recent epidemiological results support the notion that elevated fluoride intake during early development can result in IQ deficits that may be considerable. Recognition of neurotoxic risks is necessary when determining the safety of fluoride-contaminated drinking water and fluoride uses for preventive dentistry purposes.

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Section: Resultsmentioning

confidence: 99%

Developmental fluoride neurotoxicity: an updated review

Grandjean

2019

Environ Health

141

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“…Malin and Till 2015 collected information about the diagnosis by using the National Survey of Children's Health (NSCH), a cross-sectional digital survey in which parents were asked questions regarding the well-being of children in their household, including whether those children had received an ADHD diagnosis. The same data were used by Perrott 2018 [45]. Instead, Adkins et al, 2022 asked parents to complete the Behavior Assessment System for Children-2 (BASC-2), a tool that consists of 16 primary measurement domains (including the Hyperactivity domain) but is not specific for ADHD diagnosis.…”

Section: Resultsmentioning

confidence: 99%

“…Its ecological design forces one to categorize fluoride exposure as exposed versus non-exposed, regardless of individual fluoride levels. Moreover, although Malin and Till 2015 adjusted their statistical model for socio-economic status, they did not adjust for several other confounders subsequently included by Perrott 2018 [45]. The latter performed multiple regression analysis on the same data as Malin and Till 2015, by including other variables considered as ADHD-related in a study by Huber et al [50].…”

Section: Discussionmentioning

confidence: 99%

Fluoride Exposure and ADHD: A Systematic Review of Epidemiological Studies

et al. 2023

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Background and objectives: Attention deficit hyperactivity disorder (ADHD) is a childhood-onset neurodevelopmental disorder characterized by two dimensions: inattentiveness and hyperactivity/impulsivity. ADHD may be the result of complex interactions between genetic, biological and environmental factors possibly including fluoride exposure. Materials and methods: A literature search was performed on 31 March 2023 in the following databases: PubMed, Embase and Web of Science. We defined the following inclusion criteria according to the PECOS statement: a healthy child and adolescent population (P), fluoride exposure of any type (E), comparison with low or null exposure (C), ADHD spectrum disorder (O), and ecological, cross-sectional, case–control and cohort studies (S). Results: We found eight eligible records corresponding to seven different studies investigating the effect of fluoride exposure on children and adolescents. One study had a cohort design and one a case–control one, while five were cross-sectional. Only three studies applied validated questionnaires for the purpose of ADHD diagnosis. As regards exposure assessment, levels of fluoride in urine and tap water were, respectively used in three and two studies, while two used both. Three studies reported a positive association with ADHD risk, all assessing exposure through fluoride levels. By using urinary fluoride, conversely, a positive correlation with inattention, internalizing symptoms, cognitive and psychosomatic problems was found in three studies, but no relation was found in the other one. Conclusions: The present review suggests that early exposure to fluoride may have neurotoxic effects on neurodevelopment affecting behavioral, cognitive and psychosomatic symptoms related to ADHD diagnosis. However, due to the heterogeneity of the studies included, current evidence does not allow to conclusively confirm that fluoride exposure is specifically linked to ADHD development.

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“…Other studies on attention outcomes found an association between water fluoridation and diagnosis of ADHD in Canada, although data on child U‐F did not replicate this association (Riddell, Malin, Flora, McCague, & Till, 2019), which is consistent with the ELEMENT study of child U‐F and IQ (Bashash et al., 2017). Similarly, increased risk of ADHD was reported to be associated with water fluoridation at the state level in the United States (Malin & Till, 2015), although inclusion of mean elevation at the residence as a covariate made the association nonsignificant (Perrott, 2018).…”

Section: Discussionmentioning

confidence: 99%

A Benchmark Dose Analysis for Maternal Pregnancy Urine‐Fluoride and IQ in Children

Grandjean

Till

et al. 2021

Risk Analysis

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As a guide to establishing a safe exposure level for fluoride exposure in pregnancy, we applied benchmark dose modeling to data from two prospective birth cohort studies. We included mother–child pairs from the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) cohort in Mexico and the Maternal‐Infant Research on Environmental Chemicals (MIREC) cohort in Canada. Maternal urinary fluoride concentrations (U‐F, in mg/L, creatinine‐adjusted) were measured in urine samples obtained during pregnancy. Children were assessed for intelligence quotient (IQ) at age 4 (n = 211) and between six and 12 years (n = 287) in the ELEMENT cohort, and three to four years (n = 407) in the MIREC cohort. We calculated covariate‐adjusted regression coefficients and their standard errors to assess the association of maternal U‐F concentrations with children's IQ measures. Assuming a benchmark response of 1 IQ point, we derived benchmark concentrations (BMCs) and benchmark concentration levels (BMCLs). No deviation from linearity was detected in the dose–response relationships, but boys showed lower BMC values than girls. Using a linear slope for the joint cohort data, the BMC for maternal U‐F associated with a 1‐point decrease in IQ scores was 0.31 mg/L (BMCL, 0.19 mg/L) for the youngest boys and girls in the two cohorts, and 0.33 mg/L (BMCL, 0.20 mg/L) for the MIREC cohort and the older ELEMENT children. Thus, the joint data show a BMCL in terms of the adjusted U‐F concentrations in the pregnant women of approximately 0.2 mg/L. These results can be used to guide decisions on preventing excess fluoride exposure in pregnant women.

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Fluoridation and attention deficit hyperactivity disorder – a critique of Malin and Till (2015)

Cited by 7 publications

References 7 publications

Developmental fluoride neurotoxicity: an updated review

Developmental fluoride neurotoxicity: an updated review

Fluoride Exposure and ADHD: A Systematic Review of Epidemiological Studies

A Benchmark Dose Analysis for Maternal Pregnancy Urine‐Fluoride and IQ in Children

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