Association of exposure to selected chemical contaminants with diabetes mellitus in Chinese adults: Mixture associations and metabolic mediation in the PNFS study.

Despite existing research on the adverse association of individual chemical contaminants and diabetes mellitus (DM), the joint effects of co-exposure to multiple contaminants remain largely unclear. This study investigated the associations between urinary biomarkers of four common chemical contaminants, including acrylamide, 3-monochloropropane-1,2-diol, glycidol, and thiocyanate, and DM prevalence in a Chinese population, as well as potential mediation by plasma metabolites. Bayesian kernel machine regression (BKMR) and quantile g-computation analyses demonstrated a significant joint effect of the contaminant mixture on DM prevalence. BKMR with hierarchical variable selection identified thiocyanate as the key contributor to this joint effect. We observed a nonlinear relationship between thiocyanate exposure and DM prevalence. Metabolomics analysis revealed significant associations between thiocyanate exposure and 11 plasma metabolites. Mediation analysis identified acrylic acid and glucose as the most important mediators, accounting for 36.19 % and 35.22 % of the association of thiocyanate exposure with DM prevalence, respectively. Our findings provide novel insights into the complex relationships between exposure to chemical contaminant mixtures, metabolic alterations, and DM prevalence, highlighting the importance of considering mixture effects in environmental health research and suggesting potential targets for diabetes prevention strategies.