Assessing the association between pesticide exposure and cognitive development in rural Costa Rican children living in organic and conventional coffee farms.

We examined the association between pesticide exposure and cognitive development among rural Costa Rican children in a cross-sectional study. Study participants aged 4-10 years included 17 children whose parents worked in La Amistad organic coffee plantation and 18 Las Mellizas children whose parents worked in their own small conventional coffee farms. Two spot-urine samples were collected from each participant and analyzed for organophosphorus and pyrethroids pesticide metabolites. We administered the computerized Behavioral Assessment and Research System (BARS), a figure-drawing task, and a long-term memory test to evaluate study participant's cognitive development. Although urinary pesticide metabolite levels did not vary considerably between these two groups of children, we found that Las Mellizas children performed better in BARS and the figure drawing tests than did La Amistad. The results from the linear mixed-effects models suggested that family socioeconomic status (SES) might be a significant contributor to the variation of the outcomes of the neurobehavioral tests. The effect of pesticide exposure, however, as measured in a snapshot fashion, did not play a significant role to the performance of the cognitive development evaluation. Regardless of the study limitations, needed effort should be devoted to the improvement of the SES on the La Amistad families so that their children's cognitive development would not be compromised further. Additionally, future studies should focus on addressing the limitations imposed on the snapshot assessment of pesticide exposure and on conducting cognitive development evaluation so the link between childhood pesticide exposure and their cognitive development can be thoroughly investigated.