Diesel Exhaust Impairs Blood Vessels
Breathing diesel exhaust at levels typically found in large cities for as little as an hour can disrupt important blood vessel functions, suggesting a possible mechanism for increased heart attack rates during periods of high air pollution.
A chamber study by cardiologists at the University of Edinburgh used a double-blind, randomized, cross-over design to assess the effects of diesel fumes in two important and complementary aspects of vascular function: the regulation of vascular tone and the ability to remove of small blood clots. Both functions were impaired and are plausibly related to the cardiovascular effects of air pollution.
The study involved 30 healthy, non-smoking men, aged 20 to 38, who were evaluated during two one-hour tests, two weeks apart. During each test, the men were exposed to either clean air or diesel exhaust from an idling engine, while riding a stationary bicycle for 15-minute stretches inside an exposure chamber. Participants received injections of a vasodilator and researchers measured their blood flow rates during and after exposure. The study found that exposure to diesel exhaust during exercise reduced the blood vessels’ ability to dilate, or expand, and decreased levels on an enzyme that helps prevent clots from forming in the blood
According to the authors, these findings provide a plausible mechanism linking air pollution to the development of atherothrombosis and heart attacks.
Mills NL, Törnqvist H, Robinson, SD, Gonzalez M, Darnley K, MacNee W, Boon NA, Donaldson K, Blomberg A, Sandstrom T, Newby DE. Diesel Exhaust Inhalation Causes Vascular Dysfunction and Impaired Endogenous Fibrinolysis. Circulation 2005; 112:3930-3936.
For a copy of the abstract click here.
