A two-wave panel biomonitoring study of changes in urinary pesticide metabolites and their associations with liver function and inflammatory markers.

Previous studies suggest that pesticide exposure is associated with impaired liver function and chronic inflammation. However, most evidence comes from cross-sectional designs and the health effects of within-individual changes in pesticide exposure remain largely unexplored. We used a two-wave longitudinal panel design (n = 225) with repeated biomonitoring measurements collected in 2019 and 2023 to assess the intra-individual changes in urinary pesticide metabolites and their associations with concurrent alterations in liver function and inflammatory markers. All models were adjusted for major demographic and lifestyle covariates, body mass index, and urine specific gravity. Despite an overall decline in pesticide exposure, changes in urinary pesticide metabolites were positively associated with alterations in liver function and inflammatory markers. Specifically, Bayesian kernel machine regression showed that changes in urinary pesticide metabolites were positively associated with changes in alkaline phosphatase, total protein, and globulin, and changes in systemic inflammatory markers, including white blood cell counts, platelet count, neutrophil count, and inflammation index. After controlling for multiple comparisons using the Benjamini-Hochberg false discovery rate, changes in trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid were negatively associated with changes in total bilirubin (β = -3.34; 95% CI: -5.05, -1.62). In contrast, changes in 3-phenoxybenzoic acid were positively associated with changes in total bilirubin (β = 2.75; 95% CI: 0.73, 4.78). Mediation analysis indicated that changes in platelet-based inflammatory markers, including platelet count, platelet-to-lymphocyte ratio, and systemic immune-inflammation index, partially mediated the association between para-nitrophenol and changes in total protein and globulin. Overall, temporal increases in pesticide exposure were associated with alterations in liver function and inflammation, and systemic inflammation may be a critical pathway linking pesticide exposure to immune-related hepatic effects.