These results substantially expand our understanding about how air pollution contributes to cardiovascular disease by showing that exposure is associated with a cascade of adverse effects.

—C. Arden Pope, Ph.D., lead author, Brigham Young University

For this study, investigators collected blood from healthy, non-smoking, young adults over three study periods that included episodes of elevated PM_2.5 levels. The researchers found that periodic exposure to fine particulate matter was associated with several abnormal changes in the blood that are markers for cardiovascular disease. As air pollution rose, they found:

• small, micro-particles indicating cell injury and death significantly increased in number;

• levels of proteins that inhibit blood vessel growth increased; and

• proteins that signify blood-vessel inflammation also showed significant increases.

Episodic PM_2.5 exposures are associated with increased endothelial cell apoptosis, an anti-angiogenic plasma profile, and elevated levels of circulating monocytes, and T, but not B, lymphocytes. These changes could contribute to the pathogenic sequelae of atherogenesis and acute coronary events.

—Pope et al.

These findings suggest that living in a polluted environment could promote the development of high blood pressure, heart disease, and stroke more pervasively and at an earlier stage than previously thought. Although we have known for some time that air pollution can trigger heart attacks or strokes in susceptible, high-risk individuals, the finding that it could also affect even seemingly healthy individuals suggests that increased levels of air pollution are of concern to all of us, not just the sick or the elderly.

—Aruni Bhatnagar, Ph.D., co-author, University of Louisville

Study participants included 72 healthy, non-smoking, adults in Provo, Utah. Their average age was 23, most were white, and more than half were male. During the winters of 2013, 2014, and 2015, participants provided blood samples, which researchers then tested for markers of cardiovascular disease. Due to the unique weather and geographical features of Provo, they were able to evaluate these informative blood markers with various levels of air pollution.

The researchers noted that the third study year, 2015, was relatively unpolluted, which could have affected the results.

The National Institutes of Health funded the study.

Resources

• C A Pope, Aruni Bhatnagar, James McCracken, Wesley T Abplanalp, Daniel J Conklin and Timothy E O’Toole (2016) “Exposure to Fine Particulate Air Pollution Is Associated with Endothelial Injury and Systemic Inflammation” Circulation Research doi: 10.1161/CIRCRESAHA.116.309279