In men younger than 50 years, even just a reduction in the number of cigarettes smoked may decrease the risk of ischemic stroke, according to a population-based, case-control study.
The odds ratio for a stroke was 1.21 for men who smoked fewer than 11 cigarettes per day, compared with nonsmokers, and 5.24 for those who smoked 40 or more per day, reported Janina Markidan and her coinvestigators in Stroke.
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A prior study showed a similar relationship in young women, but the researchers decided to conduct a follow-up study in men in order to eliminate hormonal confounders (Stroke. 2008 Sep;39[9]:2439-43).
Ms. Markidan and her colleagues used data from the Stroke Prevention in Young Men Study, which recruited 615 men who had experienced a stroke in the previous three years, and compared these men with 530 age-, ethnicity-, and geography-matched controls.
There were some statistically significant differences in the two populations: Cases had lower levels of education and had greater incidences of hypertension, diabetes, myocardial infarction, angina, and obesity (all P < .05).
Current smokers were identified as those who had smoked more than 100 cigarettes in their lifetime and who had smoked a cigarette in the 30 days preceding the stroke. Never smokers were those who had smoked fewer than 100 cigarettes in their lifetime or who had never smoked five packs.
Compared with never smokers, current smokers had an odds ratio for stroke of 1.88 (95% confidence interval, 1.44-2.44). When the researchers stratified smokers by the number of cigarettes smoked, the stroke risk appeared to be dose dependent in the fully adjusted models: The OR for 1-10 cigarettes/day was 1.21 (95% CI, 0.83-1.77), 1.64 for 11-20 cigarettes/day (95% CI, 1.10-2.43), 3.51 for 21-39 cigarettes/day (95% CI, 1.65-7.45), and 5.24 for 40 or more cigarettes/day (95% CI, 1.90-14.42).