Neurobehavioral Performance in Preschool Children Exposed Postnatally to Organophosphates in Agricultural Regions, Northern Thailand

Abstract

Evidence of the effects of postnatal exposure to organophosphates (OPs) on children's neurodevelopment remains limited but crucial. This cross-sectional study evaluated exposure to OPs and neurobehavioral performance in 172 preschool children. Urinary dialkyl phosphate (DAP) metabolites, biomarkers for exposure to OPs, were measured. The neurobehavioral assessments included motor skills, memory, and cognitive function, measured using the Purdue pegboard test, digit span test, object memory test, and visual-motor integration. Multiple linear regression models were employed to explore the associations between urinary DAP metabolite levels and neurobehavioral performance, adjusting for potential confounders. Findings revealed that children of farming parents had higher urinary levels of dimethylphosphate (DMP) (Beta = 0.730, 95% CI = 0.138, 1.322, p value = 0.016) and diethylphosphate (DEP) (Beta = 0.668, 95% CI = 0.044, 1.291, p value = 0.036). Additionally, high fruit consumption correlated with increased urinary DEP levels (Beta = 0.398, 95% CI = 0.063, 0.733, p value = 0.020). Critically, elevated urinary DEP was associated with poorer fine motor coordination, affecting performance in the Purdue pegboard test for the dominant hand (Beta = -0.428, 95% CI = -0.661, -0.194, p value < 0.001), the preferred hand (Beta = -0.376, 95% CI = -0.603, -0.149, p value = 0.001), and both hands (Beta = -0.524, 95% CI = -0.773, -0.276, p value < 0.001). These findings highlight the role of parental occupation and diet in children's OP exposure and suggest that OP exposure negatively impacts fine motor coordination. Targeted interventions, such as promoting organic diets, enhancing workplace safety, and ongoing biomonitoring, are vital to reduce neurodevelopmental risks for vulnerable populations.

Keywords: children; neurobehavior; neurodevelopment; organophosphate; pesticide.