Long-term exposure to PM2.5 components and lipid profiles in WTC Health Program general responders

Previous studies have shown that fine particulate matter (PM2.5) is associated with elevated blood lipids, but very few studies have examined the associations with specific constituents of PM2.5. We studied the associations between exposure to annual PM2.5 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 PM2.5 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.