Association between PM2.5 chemical components and dyslipidemia in middle‑aged and older Chinese adults: a prospective cohort study

Ambient particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5) components in self-reported dyslipidemia remain unclear. This study aimed to investigate the associations between specific PM2.5 constituents and self-reported dyslipidemia. This study included 17,213 participants aged ≥ 45 years from the China Health and Retirement Longitudinal Study. Five major PM2.5 components (black carbon BC, organic matter OM, sulfate SO4²⁻, nitrate NO3⁻, and ammonium NH4⁺) were estimated using Tracking Air Pollution. Multivariable logistic and Cox proportional hazards models were used to estimate associations. Stratified analyses by age, gender, and residence were performed, and weighted quantile sum (WQS) regression was used to assess mixture associations. At baseline, 1,696 participants (9.9%) had self-reported dyslipidemia. In longitudinal analysis, all components remained significantly associated with incident self-reported dyslipidemia, with hazard ratios ranging from 1.06 to 1.10. NO3⁻ showed the strongest associations in both analyses. Associations were more pronounced in participants aged ≥ 65 years. Mixture analysis revealed significant joint associations (WQS OR = 1.15, 95% CI: 1.08–1.23), with NO3⁻ contributing the highest weight. Modeled exposure-response relationships indicated non-linear associations, with increasing risk at higher exposure levels. In conclusion, this observational study suggests that exposure to PM2.5 components, particularly NO3⁻, was associated with increased self-reported dyslipidemia risk in middle‑aged and older adults.