Mexican Study Shows an Inverse Association between Fluoride Exposure and IQ in Children

OP V – 2 Prenatal fluoride exposure and neurobehavior among children 1–3 years of age in Mexico

Author: Thomas D, Sanchez B, Peterson K, Basu N, Martinez-Mier EA, Mercado-Garcia A, Hernandez-Avila M, Till C, Bashash M, Hu H, Tellez-Rojo MM.

Journal Name: Occupational & Environmental Medicine

Publish Date: 03-18-2018



Recent studies report an inverse association between fluoride (F) exposure and IQ in children, but few included individual measures of exposure or assessed associations with prenatal exposure using a prospective study design.


This study utilized the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) birth cohort and archived pregnancy samples to study prenatal F exposure and its association with subsequent child neurobehavioral outcomes at ages 1, 2 and 3 years. A Generalised Mixed Model (GMM) was used to model the association between mean creatinine-adjusted urinary F (MUFcr), averaged over three trimesters, and Mental Development Index (MDI), a subscale of the Bayley Scales of Infant Development-II (BSID-II) test, among 401 mother-infant pairs. The analysis controlled for maternal age, education, marital status, ELEMENT cohort, child’s sex, and child’s age.


The median MUFcr was 0.835/mg/L (minimum: 0.195, maximum: 3.673). MUFcr was significantly inversely associated with offspring MDI scores, with an increase in MUFcr of 0.5/mg/L (roughly the interquartile range value) corresponding to a decrease in MDI of -1.20 points (95%CI: -2.19,–0.20).


Our findings add to our team’s recently published report on prenatal fluoride and cognition at ages 4 and 6–12 years by suggesting that higher in utero exposure to F has an adverse impact on offspring cognitive development that can be detected earlier, in the first three years of life.

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