RT Journal Article SR Electronic T1 OP V – 2 Prenatal fluoride exposure and neurobehavior among children 1–3 years of age in mexico JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP A10 OP A10 DO 10.1136/oemed-2018-ISEEabstracts.23 VO 75 IS Suppl 1 A1 Deena Thomas A1 Brisa Sanchez A1 Karen Peterson A1 Niladri Basu A1 E Angeles Martinez-Mier A1 Adriana Mercado-Garcia A1 Mauricio Hernandez-Avila A1 Christine Till A1 Morteza Bashash A1 Howard Hu A1 Martha M Tellez-Rojo YR 2018 UL http://oem.bmj.com/content/75/Suppl_1/A10.1.abstract AB Background/aim 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.Methods This study utilised 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.Results 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).Conclusion 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.