Project title: Organophosphates in Urine and House Dust and Associations with Asthma Respiratory Health Outcomes in an Agricultural Children’s Cohort
Completed in: 2022 | Faculty advisor: Elaine M. Faustman
Organophosphate (OP) pesticides are extensively used to support agricultural practices in Washington State. OP exposure is associated with both asthmatic populations and agricultural communities. The objective of this thesis is to investigate the correlation between OP pesticide exposure in agricultural community, with respiratory health outcomes, associated with asthma. As part of a Children’s Cohort Study, Farmworkers (FW), Non-Farmworkers (NFW), each with a referent child, were recruited in the Yakima Valley of Eastern Washington. House dust and urine samples were collected in 3 seasons in 2 different study periods (2005 and 2011) according to pome fruit growth cycles. Health questionnaires were distributed to each household, and clinically recognized asthma-related respiratory data was collected by study staff. Concentrations of OP parent compounds in house dust samples, and dialkyl phosphate metabolites (DAPs) in urine samples were quantified and statistically evaluated against various asthma-related respiratory outcomes collected on the administered health survey. Our results show a significant association between OP compounds and their metabolites with asthma-related respiratory health outcomes in our adult population. Among adults living in the agricultural community, an increase in OP compound and metabolite concentration was significantly related to a decrease in asthmatic outcome. We found these associations between dust OP biomarker and asthmatic outcome and urine OP biomarkers with asthmatic outcome, were not significant in the children group. However, the exposure-health outcome association was significantly different between males and females among this group (p= 0.043) resulting in significantly different slopes for boys than girls. Previous studies from this research cohort have identified specific urinary microRNAs, including miR-223, that are associated with our FW and NFW occupational status and in a dose-response fashion to OP urinary DAPs from our study population. In this field, research studies have focused on miR-223 and its role as a regulatory molecule capable of influencing asthma pathogenesis. In our future directions we explore the urinary microRNA profiles associated with this pesticide exposed population and their potential as asthma and respiratory disease biomarkers.