Secondhand Smoke Increases Stroke Risk

Healthnotes Newswire (October 6, 2005)—Women who smoke cigarettes have a greatly increased risk of suffering from a stroke if their spouse also smokes, reports the journal Stroke (2005;36:74–6).

Secondhand smoke, also known as environmental or passive tobacco smoke, is a mixture of the smoke from a lit cigarette and the exhaled smoke from the smoker. Environmental tobacco smoke is a human carcinogen, accounting for about 3,000 deaths from lung cancer in nonsmokers each year. It is also responsible for about 40,000 deaths from heart disease in nonsmokers each year.

Children are particularly vulnerable to the adverse effects of secondhand smoke. Exposure increases the number and severity of asthma attacks and ear infections, young children may develop serious lower respiratory infections such as pneumonia and bronchitis, and infants are more likely to die from sudden infant death syndrome (SIDS).

The new study investigated the possible connection between exposure to secondhand smoke and the risk of stroke in 5,379 women. Participants were asked about their smoking status (whether a current smoker or nonsmoker), number of cigarettes smoked per day, number of years of smoking, and whether their spouses smoke. In the eight years following the initial interview, the number of strokes among the women was recorded. Strokes were classified according to type: ischemic (reduced blood flow to part of the brain) or hemorrhagic (a bleed into the brain).

Among women who smoked, the risk of strokes was almost six times higher and the risk of ischemic stroke was nearly five times higher in the women whose spouses also smoked than in women with nonsmoking spouses. It is interesting to note that, among nonsmoking women, the spouse’s smoking status did not affect their risk of stroke. This finding may be explained by the tendency for spouses of nonsmokers to avoid smoking around their wives. It is also possible that the spouses of the nonsmoking women may have quit smoking during the follow-up period, thereby decreasing the risk of stroke in their partners.

Stopping smoking decreases heart attack risk and helps improve lung function. Ten years after quitting, the risk of developing lung cancer drops to one-half of that of current smokers. Within 5 to 15 years of quitting smoking, the risk of stroke is similar to that of someone who has never smoked. These results add to the growing body of evidence about smoking’s negative effects and provide smokers with more incentive to quit.