Air pollution’s effect on the heart
Findings from a decade-long study showed that long-term exposure to air pollution speeds up calcification in arteries that supply blood to the heart. The new findings revealed the biological processes underlying the link between air pollution exposure and increased risk of heart disease.
Using data from the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air), researchers used home addresses of more than 6,795 people from six U.S. states to assess exposure to air pollutants, including particulate matter smaller than 2.5 microns (PM2.5), nitrogen oxides, and black carbon. Over a period of ten years, CT scans were used to repeatedly measure calcium deposits in the coronary arteries of each participant.
Analysis of the MESA Air data showed that air pollution sped up calcification of the arteries in a way that was consistent with acceleration of atherosclerosis, a condition associated with heart disease. Study participants showed a 20 percent acceleration in the rate of calcium deposits for every 5 micrograms per cubic meter increase in PM2.5, or 35 parts per billion increase in concentration of nitrogen oxides. From 2000 to 2010, study participants experienced an average PM2.5 exposure of 14.2 micrograms per cubic meter, with a range of 9.2 to 22.6. For comparison, today’s U.S. National Ambient Air Quality Standards allow an annual average PM2.5 concentration of 12 micrograms per meter.
Citation: Kaufman JD, Adar SD, Barr RG, Budoff M, Burke GL, Curl CL, Daviglus ML, Roux AV, Gassett AJ, Jacobs DR Jr, Kronmal R, Larson TV, Navas-Acien A, Olives C, Sampson PD, Sheppard L, Siscovick DS, Stein JH, Szpiro AA, Watson KE. 2016. Association between air pollution and coronary artery calcification within six metropolitan areas in the USA (the Multi-Ethnic Study of Atherosclerosis and Air Pollution): a longitudinal cohort study. Lancet; doi:10.1016/S0140-6736(16)00378-0 [Online 24 May 2016].