Passive smoking shown to disrupt heart

2019-03-06 09:16:25

By Greg Miller Passively breathing cigarette smoke for just 30 minutes disrupts the blood vessels supplying the heart in healthy non-smokers, say researchers in Japan. The finding may help explain why heart disease accounts for the majority of deaths attributed to passive smoking. The study included 30 male medical students, half of whom were regular smokers. Doctors tested the subjects’ coronary circulation before and after a 30-minute exposure to tobacco smoke using a modified version of a test commonly used to assess coronary artery disease. They found that smoke exposure impaired the responsiveness of the endothelial cells that line the chambers and blood vessels of the heart in non-smokers. Endothelial cell function was impaired in smokers even before the smoke exposure. “Loss of endothelial function is one of the first steps towards disease,” says William Parmley, a cardiologist at the University of California, San Francisco. Endothelial cells play an important role in regulating blood flow to the heart, and when they do not work properly, the risk of developing blood clots and narrow, hardened arteries increases. The results of the Japanese study may help explain why exposure to relatively small amounts of tobacco smoke lead to big increases in the risk of heart disease, says Nicholas Wald at St. Bartholomew’s and the Royal London School of Medicine. Living with a smoker, for example, increases the risk of a heart attack by about a third – a 20-a-day smoker doubles their risk. Wald says understanding the link between second hand smoke and heart disease is critically important because heart disease is fairly common in the non-smoking population. That means even a small added risk can lead to many extra deaths. Regulations designed to protect non-smokers from the dangers of second hand smoke have been put in place in some regions, most notably in California. There, smoking is forbidden in all workplaces, including restaurants and bars. But in the UK, Wald says, attitudes tend to be more permissive. “The irritation and health risks of passive smoking, while accepted, don’t seem to have led to positive change.” Journal reference: Journal of the American Medical Association (vol 286,