UC Davis

Fine particles (PM_2.5) are known to increase risks of cardiovascular diseases, but it is unclear how they affect plasma lipid levels. In this study, we examined the associations between PM_2.5 exposure and lipid/lipoprotein levels from 2289 midlife women enrolled in the longitudinal Study of Women's Health Across the Nation. The average exposure to PM_2.5 and gaseous co-pollutants during the prior one year, six months, 30 days, and one day were estimated for each woman based on U.S. Environmental Protection Agency ambient monitoring data. Blood samples were collected annually from 1999 to 2005 and analyzed for lipids/lipoproteins. Mixed-effect models were used to account for repeated measures for each woman, adjusted for demographic, health and behavior covariates. PM_2.5 exposures, especially the long-term exposure, were negatively associated with protective lipoproteins, and positively associated with atherogenic lipoproteins. For example, each 3 μg/m³ increase of one-year PM_2.5 exposure was associated with decreases of -0.7% (-1.4%, -0.1%) in high-density lipoprotein cholesterols and -0.6% (-1.1%, -0.1%) in apolipoprotein A1 (ApoA1), as well as increases of 3.8% (1.0%, 6.6%) in lipoprotein(a) and 1.4% (0.5%, 2.3%) in the ratio of apolipoprotein B (ApoB)/ApoA1. In stratified analysis, increased atherogenic lipoproteins were mainly observed in women without dyslipidemia, and both increased atherogenic lipoproteins and reduced protective lipoproteins were observed among women in perimenopause. In summary, PM_2.5 exposure was associated with adverse lipid level changes, and thus, may increase cardiovascular risks in midlife women.