Associations of PM2.5 and its constituents with blood lipids: A national longitudinal study in China

• PM2.5 constituents are linked to adverse lipid changes in a longitudinal study. • SIA components show the strongest associations with adverse blood lipid levels. • PM 2.5 constituents exhibit non-linear and non-threshold exposure-response curves. • Males, the elderly, and those with abnormal BMI are more susceptible to exposure. The association between fine particulate matter (PM 2.5 ) chemical constituents and blood lipid levels remains unclear. This longitudinal study, leveraging data from a comprehensive national survey across 31 provinces in mainland China, aimed to assess the associations between exposure to PM 2.5 constituents and blood lipid metabolism. Utilizing data from the China National Stroke Screening Survey (CNSSS), we included 292,754 participants accounting for 683,759 visits recorded between 2013 and 2019. To investigate the longitudinal relationship between PM 2.5 , its five constituents (ammonium, sulfate, nitrate, black carbon (BC), and organic matter (OM)), and four blood lipid indicators (low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol (HDLC), triglyceride (TG), and total cholesterol (TC)), we employed linear fixed-effects panel regression models. Each interquartile range (IQR) increase in PM 2.5 (lag 0-3 months) was associated with significant increases in LDLC (3.44%, 95% CI: 3.07–3.80) and TC (2.99%, 95% CI: 2.70–3.28), and a decrease in HDLC (-0.89%, 95% CI: -1.17 to -0.62). For constituents, ammonium and nitrate showed the strongest associations with LDLC (4.66% and 4.76%, respectively) and TC (3.72% and 3.60%, respectively). TG levels were positively associated with secondary inorganic aerosols, most notably sulfate (2.91%, 95% CI: 2.50–3.33). Significant negative correlations with HDLC were observed for BC (-0.46%, 95% CI: -0.72 to -0.19) and sulfate (-0.71%, 95% CI: -1.04 to -0.38). The exposure-response relationships between the constituents and blood lipid indicators were predominantly nonlinear, characterized by a plateau at higher concentration levels. Our results indicate that exposure to PM 2.5 and its constituents, especially inorganic aerosol components, was strongly associated with adverse blood lipid levels. The findings of our study provide critical insights into policy development aimed at enhancing the management and control of PM 2.5 pollution.