Childhood Exposures to Ozone

Air pollution is a ubiquitous environmental exposure that threatens the health of people worldwide, in no small part due to the development and exacerbation of cardiovascular diseases. Daily fluctuations in pollution have been associated with acute changes in subclinical measures of disease (eg, systemic inflammation, endothelial dysfunction, and vasoconstriction), and increases in risk of overt cardiovascular events (eg, myocardial infarction, stroke, and mortality), as well. Moreover, living in a more polluted area over a long period of time has been shown to elevate risks of cardiovascular morbidity and mortality.1–3 With no evidence of a safe threshold, health impacts are detectable even in areas with concentrations below current regulatory standards of the United States and abroad. In fact, the World Health Organization has estimated that more than one million deaths per year are attributable to outdoor air pollution.4Article see p 1614The Environmental Protection Agency has recently reported that >100 million Americans live in areas exceeding the national ambient air quality standards for 2 key pollutants, fine particulate matter (PM2.5) and ozone (O3).5 Although robust evidence links PM2.5 to cardiovascular morbidity and mortality,1 O3 is most often linked to adverse respiratory endpoints such as asthma exacerbations.3 Nevertheless, a growing body of animal evidence supports the hypothesis that long-term exposures to PM2.5 and O3 can have harmful cardiovascular effects, including potentiating the formation of atherosclerotic lesions.6–8 Few human studies have evaluated this issue, especially with respect to O3, and even fewer have investigated the cardiovascular health impacts of childhood exposures.In this issue of Circulation , Breton and colleagues present their findings of a cross-sectional analysis of childhood exposures to air pollutants and …