Griffith Bell, Ph.D., Joel D. Kaufman, M.D.
University of Washington
P50ES015915, F31ES025096, P30ES007033
An NIEHS-funded study found an association between exposure to higher levels of traffic-related air pollution and lower levels of high-density lipoprotein (HDL) cholesterol, or good cholesterol. Since low HDL cholesterol is a risk factor for cardiovascular diseases, the new findings offer possible insight into how air pollution exposure increases cardiovascular disease risk.
To examine the relationship between HDL levels and air pollution, the researchers studied 6,654 middle-aged and older participants in the Multi-Ethnic Study of Atherosclerosis Air Pollution study. Individual residential exposure to ambient fine particulate pollution exposure (PM2.5) and black carbon — both components of traffic-related air pollution — were averaged for exposure periods of 12 months, 3 months, and 2 weeks. Because HDL particle numbers have been recently shown to reflect HDL’s heart-protective qualities better than HDL cholesterol levels, the researchers measured both HDL cholesterol and particle numbers. In the body, HDL particles carry HDL cholesterol.
The analysis revealed that participants living in areas with higher levels of traffic-related air pollution tended to have lower HDL levels. Specifically, exposure to higher concentrations of black carbon over a 1-year period was associated with a 1.68 milligram per deciliter lower HDL cholesterol and a 0.55 micromole per liter lower HDL particle number. For the 3-month averaged exposure period, 5.0 milligrams per cubic meter higher exposure to PM2.5 was associated with a HDL particle number that was 0.64 micromole per liter lower, but HDL cholesterol levels dropped only 0.05 milligram per deciliter.
Citation: Bell G, Mora S, Greenland P, Tsai M, Gill E, Kaufman JD. 2017. Association of air pollution exposures with high-density lipoprotein cholesterol and particle number: The multi-ethnic study of Atherosclerosis. Arterioscler Thromb Vasc Biol 37(5):976-982.