8287348 Evaluation and update of an algorithm for quantitatively estimating non-occupational pesticide exposure for spouses in the agricultural health study

<h3>Introduction</h3> An algorithm to estimate non-occupational pesticide exposure from take-home, agricultural drift, and residential use pathways was previously developed for spouses of farmers who applied pesticides in the Agricultural Health Study (AHS). The algorithm combined participant- and pesticide active ingredient-specific information with pathway weights derived from meta-analyses of published data through 2015. We updated and evaluated the algorithm by expanding our literature review and analysis to include studies published in the last 10 years. <h3>Methods</h3> We conducted an updated literature review through 2024 and abstracted published measurements. For each pathway, we examined the relative differences (RD) in indoor dust pesticide concentrations using mixed-effect meta-regression models, which we used to update the algorithm. <h3>Results</h3> We added exposure measurements from 9 publications to the original 10 publications. In total, this provided 58, 68, and 93 summary statistics for the take-home, agricultural drift, and residential use pathways, respectively. The algorithm’s assumption that non-occupational exposure increases with increasing number of days of an active ingredient’s agricultural use was confirmed by AHS-specific dust measurements. For the take-home pathway, weights increased from 2.3 (95%CI: 1.5-3.3) to 3.7 (95%CI: 1.9, 7.4) in the updated algorithm based on measurements in homes with known use of the active ingredient. By contrast, the updates for the agricultural drift pathway lowered the weights for all ‘home-to-field’ distance categories; for example, the RD dropped from 3.0 (95%CI: 1.7-5.4) to 2.0 (95%CI: 1.3-3.1) for homes located &lt;100 yards from field. We found minimal changes to the residential use pathway weights. We also updated the algorithm to apply the adjustment factor for ‘time at home’ to all pathways, rather than just the take-home pathway. <h3>Discussion</h3> Our update confirmed several algorithm assumptions and provided updated pathway weights. The refined algorithm will better characterize non-occupational pesticide exposure contrast among the AHS spouses for future etiologic analyses.