Long-term Exposure to PM_2.5 Components and Lipid Profiles in World Trade Center Health Program General Responders

Previous studies have shown that fine particulate matter (PM_2.5) is associated with elevated blood lipids, but very few studies have examined the associations with specific constituents of PM_2.5. We studied the associations between exposure to annual PM_2.5 and its 14 constituents, and repeated blood lipid measurements among general responders enrolled in the World Trade Center Health Program between 2003 and 2019 (n = 44,876). We used generalized additive mixed effect models to investigate the single-pollutant associations with repeated measures of blood total cholesterol (TC), and low-density lipoprotein (LDL-C) levels. We then used linear generalized weighted quantile sum regression with a random intercept for participant ID to account for the clustering of repeated measures and evaluate the combined associations with the component mixture. A decile increase in the mixture of 14 PM_2.5 chemical components was associated with 0.375 mg/dL increase in TC levels (95% confidence Interval (CI): 0.174-0.577) and 0.302 mg/dL increase in LDL-C (95% CI: 0.063, 0.540). Lead, organic carbon, and iron were major drivers of both associations. Component-specific models also show higher TC and LDL-C levels associated with interquartile range increases in organic carbon (0.472, [95% CI: 0.027, 0.918] and 0.648 [95% CI: 0.136, 1.160]) and iron exposure (1.081, [95% CI: 0.630, 1.532] and 0.748 [95% CI 0.318, 1.178]). Effects are more pronounced among responders with higher World Trade Center exposures, suggesting increased vulnerability. These findings are highly significant for a population exposed to extreme air pollution event and susceptible to lipid alterations that might trigger cardiovascular events.