Associations Between Urinary Polycyclic Aromatic Hydrocarbons and Glycometabolic Markers and Potential Mechanisms in Healthy Older Adults: The China BAPE study

Polycyclic aromatic hydrocarbons (PAHs) have been increasingly implicated in metabolic disorders, including type 2 diabetes, yet their impact on glycometabolism in older adults remains unclear. This study investigated associations between urinary PAH metabolites and glycometabolic markers and explored underlying potential mechanisms among healthy older adults. In the China BAPE study, 70 healthy older participants were recruited and five monthly follow-up visits were conducted between September 2018 and January 2019, with the associations between six urinary PAH metabolites and five glycometabolic markers were examined in this study. We found that exposure to urinary PAH metabolites was significantly linked to elevated glycometabolic markers, and such effects were also observed for mixed PAH exposures. Urine metabolomics combined with pathway enrichment analysis revealed that PAH exposures induced metabolic perturbations involving oxidative stress, solute carrier signaling, and other diabetes-related pathways. These findings aligned with the Adverse Outcome Pathway (AOP) framework, in which potential molecular initiating events (MIEs) such as reactive oxygen species (ROS) production triggered downstream key events (KEs) in signal transduction, ultimately affecting glycometabolic function. These findings provide mechanistic evidence linking PAH exposure to glycometabolic dysregulation and underscore the importance of environmental pollutant monitoring in older adults to support metabolic health. However, the relatively small sample size and the limited coverage of measured PAH compounds may limit the generalizability and comprehensiveness of the findings, which should be validated in larger and more diverse cohorts.