Saturday, September 26, 2009

Smoking Causes Heart Attacks

Two new studies, widely reported in the news Monday, highlight the connection between smoking and heart attacks. Researchers used epidemiological data to determine the decline in heart attack rates after smoking bans went into effect. One study found 36 percent fewer heart attacks three years after smoking bans in North America and Europe, with half the the reduction occurring in the first year.

Less than 1 in 4 adults smoke, and both smokers and non-smokers suffer heart attacks, so the size of the smoking ban effect shows that smoking bans reduce heart attack risk among both smokers and non-smokers. Previous studies, however, have shown that the reduction in heart attack risk is found mainly among non-smokers.

Smoking bans typically only affect places of business. They may encourage some smokers to stop smoking completely, but the more immediate effect is to separate tobacco smoke from non-smokers. What these new studies suggest is that cigarette smoking is linked to most heart attacks among smokers and that, prior to the smoking bans, cigarette smoke triggered about half of heart attacks among non-smokers.

The heart attack risk for non-smokers exposed to low levels of tobacco smoke had long been suspected. Being in the same room with tobacco smoke for just a few minutes causes specific changes in blood and blood vessels that are clinically measurable. Most obviously, platelets clump and blood vessels constrict, two conditions that are known to cause heart attacks. People with known heart conditions have been cautioned to avoid smoky areas since the early 1990s. The smoking-ban studies, though, show how pronounced this effect is by showing that tobacco smoke led to heart attack and death in large numbers of non-smokers.

The results of these studies confirm that it is not possible to dismiss cigarette smoke as a vague danger with possible future consequences. Smokers and non-smokers alike have to regard cigarette smoke, wherever they come upon it, as a clear and present danger that has a slight chance of causing immediate death in anyone who is nearby.

One of the components of cigarette smoke that could contribute to heart attack is carbon monoxide, and fruit additives in tobacco create more carbon monoxide than the tobacco itself. The new U.S. ban on fruit-flavored cigarettes took effect Tuesday, and this too can be expected to reduce the number of heart attacks. Policymakers can look for similar rules that can reduce the prevalence of tobacco smoke and its harmful components in order to further reduce the health damage caused by tobacco.