Occupational polycyclic aromatic hydrocarbons (PAHs) exposure and aging trajectory : Epidemiologic evidence from a cohort of Chinese coke oven workers (2019-2023)

Background: Long-term effects of occupational polycyclic aromatic hydrocarbons (PAHs) on biological aging are unclear. Methods: A prospective cohort study was conducted from 2019 to 2023, involving 610 coke oven workers and 454 control workers from a water treatment plant. Biological age was calculated using the Klemera and Doubal method (KDM-BA) based on 12 clinical biomarkers, and aging acceleration (KDM-Accel) was derived. Group-based trajectory modeling (GBTM) was employed to identify distinct aging trajectories over five time points. The associations between eleven urinary mono-hydroxylated PAH metabolites (measured via HPLC-MS) and both KDM-Accel and aging trajectories were assessed using multiple linear regression and multivariable logistic regression, respectively. Results: GBTM identified three distinct aging trajectories: slow aging (14.86%), moderately accelerated aging (59.14%), and rapidly accelerated aging (26%). Higher concentrations of urinary Σ-OHPAHs (sum of all metabolites), 1-hydroxypyrene (1-OHPyr), and 2-hydroxyphenanthrene (2-OHPhe) were significantly associated with increased KDM-Accel. A natural log-unit increase in Σ-OHPAHs and 1-OHPyr was associated with a 0.029-year and 0.028-year increase in KDM-Accel, respectively. Workers in the highest tertile (T3) of Σ-OHPAHs exposure had a 61.2% increased odds (OR = 1.612, 95% CI: 1.093–2.376) of being in the rapidly accelerated aging trajectory compared to those in the lowest tertile (T1). Similar positive dose-response relationships were observed. Conclusion: Occupational PAH exposure accelerates biological aging ; enhanced protection and early intervention are warranted.