Fluoride and Neurodevelopmental Hazard Modelling: An Assessment of Concentration-Response Analysis.

Area of Science:

• Environmental Health
• Toxicology
• Neuroscience

Background:

• A National Academies report found no evidence of fluoride as a neurodevelopmental hazard.
• Some researchers use benchmark dose modeling to establish safe fluoride levels in drinking water.
• This study assesses data suitability for modeling fluoride's impact on cognition.

Purpose of the Study:

• Evaluate the quality of maternal urinary fluoride (MUF) data for dose-response analysis.
• Assess the suitability of existing data for benchmark dose modeling of fluoride and cognition.
• Determine the association between fluoride exposure and cognitive outcomes.

Main Methods:

• Utilized EPA data quality criteria to evaluate study quality.
• Conducted random-effects meta-analyses (standardized mean difference and regression coefficients).
• Applied EPA benchmark dose modeling to assess fluoride-cognition relationships.

Main Results:

• All four MUF studies failed EPA quality standards for dose-response analysis.
• Meta-analysis showed no statistically significant association between MUF and cognition (β = -1.06, p = 0.42).
• Benchmark dose models did not reveal a functional relationship between fluoride exposure and cognitive outcomes (p < 0.1).

Conclusions:

• Significant data quality flaws in MUF studies preclude their use in hazard and dose-response assessments.
• Existing data are unsuitable for benchmark dose modeling of fluoride's effects on cognition.
• More robust studies in endemic fluorosis areas are required to investigate fluoride-cognition associations.