Visual Expectation Reaction Time and Attentional Control Associated with Prenatal Maternal Biomarkers of Organophosphate and Pyrethroid Exposures in a Thai Birth Cohort.

BACKGROUND:Maternal biomarkers of organophosphates (OPs) and pyrethroids (PYR) have been associated with compromised child cognitive development. Visual expectation (VExP) evaluates infant processing speed as a foundation for subsequent cognition. Prenatal exposures to pesticides among children of Thai farmworkers are significantly higher than those in the US. OBJECTIVE:We evaluated the association of prenatal urinary OP and PYR metabolites with VExP reaction time (RT), intraindividual variability in reaction time (SDRT), and percent off task and anticipatory responses. METHODS:We analyzed urinary metabolites of OPs and PYR in composited urine samples representing each trimester of pregnancy in 306 Thai farmworkers. Offspring completed VExP at 7, 12, and 18 months. In adjusted regression models, we tested the associations of OP and PYR metabolites with VExP outcomes. RESULTS:Prenatal OP metabolites were not associated with RT at 7 or 18 months. Females aged 12 months had significantly slower RT associated with first and third trimester OP metabolites and significantly higher SDRT at 12 and 18 months associated with first trimester OPs. Significantly faster RT and lower percent off task were associated with the PYR metabolite concentration in 18-month old females. Significantly higher anticipatory and lower off task rates were associated with concentrations of OP metabolites among 12 and 18 month old males. DISCUSSION:Increased intraindividual variability among females is consistent with previous parental reports of attention symptoms associated with prenatal OP metabolites. No consistent adverse associations with PYR were observed. Faster processing and learning were also associated with higher OPs and PYR metabolites at different ages.PP.