Thrombogenicity and cardiovascular effects of ambient air pollution.

Exposure to air pollution is associated with adverse effects on health. In particular, a strong epidemiologic association is observed between acute and chronic exposures to particulate matter and the occurrence of cardiovascular events, coronary artery disease, cerebrovascular disease and venous thromboembolism, especially among older people and people with diabetes and previous cardiovascular conditions. Multiple mechanisms have been postulated to cause the increase in atherothrombotic and thromboembolic events, including the activation by particulate matter of inflammatory pathways and hemostasis factors, production of reactive oxygen species through the oxidative stress pathway, alterations in vascular tone, and decreased heart rate variability (a marker of cardiac autonomic dysfunction and a predictor of sudden cardiac death and arrhythmias). Current knowledge on the biologic mechanisms and the clinical effect of short- and long-term exposure to particulate air pollutants is discussed, emphasizing that life expectancy improved significantly in sites where air pollutants were controlled.