Photo credit: Liji Jinaraj

A new study published in the journal Neurotoxicology demonstrates that social stressors such as economic strain or poor learning environments can magnify the negative impacts of pre-natal exposure to organophosphate (OP) pesticides. Researchers from the University of California, Berkeley investigated the interaction between social stressors and prenatal OP pesticide exposure using 329 participants in the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study. The mothers and their children were followed from pregnancy until the children reached age 7. Dialkyl phosphate metabolite concentrations (DAPs), created when OP pesticides are broken down in the body, were measured at two separate times while the mothers were pregnant. Once the children reached age 7 their IQs were calculated using the Wechsler Intelligence Scale for Children. Stressors in the children’s homes were assessed via interviews and home visits at various times over the seven-year period. While researchers found that higher levels of total social stress as well as negative parent-child relationships and poor learning environment were generally correlated with lower IQs for all test subjects, the negative correlation was significantly stronger for children of mothers who had elevated DAP levels during their pregnancy. They also found that results varied based on the sex of the children.  For example, girls born from mothers who had high DAP concentrations during pregnancy and who underwent high levels of adversity had a 10-point decrease in IQ compared to girls from mothers with high DAP concentrations who experienced less adversity. Boys, on the other hand were more likely to experience a significant drop in IQ if they were born to mothers with higher DAP concentrations during pregnancy and the boys lived in a poor learning environment. “This study suggests that children with high prenatal exposure to organophosphates who also experience specific early and persistent toxic stress may be at a greater risk for adverse cognitive development,” the authors conclude.