Air pollution ups heart attacks
Air pollution could be putting patients with heart disease at risk by affecting blood vessels and clotting, researchers said in a study published Wednesday.
A study by the University of Edinburgh in Scotland and Umea University in Sweden measured the effects of diesel exhaust on heart and blood vessel function in men who have previously suffered a heart attack.
The research, funded by the British Heart Foundation and published in the New England Journal of medicine, found that inhaling diesel exhaust caused changes in the heart's electrical activity, suggesting that air pollution reduces the amount of oxygen av ailable to the heart during exercise.
"This study provides an explanation for why patients with heart disease are more likely to be admitted to hospital on days in which air pollution levels are increased," one of the authors of the report on the study, Dr Nicholas Mills of the University of Edinburgh, said in a statement.
"Most people tend to think of air pollution as having effects on the lungs but, as this study shows, it can also have a major impact on how our heart functions," said Mills.
The study showed "That in patients with coronary heart disease, diesel exhaust can reduce the amount of oxygen available to the heart during exercise, which may increase the risk of a heart attack," said Peter Weissberg of the British Heart Foundation.
Twenty men who had suffered a previous heart attack took part in the study. The men were exposed for one hour to either filtered air or diluted diesel exhaust while intermittently riding a stationary bicycle.
Continuous electrical monitoring of the heart during the exercise test showed that inhaling diesel exhaust caused a three-fold increase in stress on the heart during exercise.
In addition, the body's ability to release the T-pA (Tissue Plasminogen Activator) protein, which can prevent blood clots from forming, was reduced by more than one-third following exposure to diesel fumes.
Diesel engines were the focus of researchers' attention for the study because they generate 10-100 times more pollutant particles than engines that run on gasoline.
Scientists could recommend that "particle traps" be fitted to diesel engines if they can show through further research that tiny pollutant particles are the chief culprit in pollution-linked heart disease, said Mills.
In the meantime, Weissberg, of the British Heart Foundation, urged heart patients to continue with their exercise regimes, "but preferably not when there is a lot of local traffic around."