Burton J. Tabaac, MD
For nearly 30 years, the dose-response relationship between tobacco consumption and stroke risk has been well established. First published in Stroke, in September 2008, this Maryland group of researchers demonstrated a strong dose-response relationship between current cigarette smoking and ischemic stroke (IS) risk among young women. This latest report demonstrates a similar dose-response effect among young men. Because of potential interactions between smoking and hormonal milieu, a separate examination of this issue in men is important. The authors are keen to note that cigarette smoking, a modifiable risk factor for ischemic stroke, has been on the rise among young adults. The team devised a population-based, case-control study of risk factors for IS in men ages 15 to 49 years, with a study population of 1145 subjects. Demographic characteristics of participants were adjusted for potential confounding factors, including age, race, education, hypertension, myocardial infarction, angina, diabetes mellitus, and body mass index.
Cases of IS were less educated and were more likely to have hypertension, diabetes mellitus, myocardial infarction, angina, and obesity. Table 2 shows that in the age-adjusted model, the odds ratio for the current smoking group compared with never smokers was 1.88 (95% confidence interval, 1.44–2.44). When the current smoking group was stratified by number of cigarettes smoked, there was a dose-response relationship for the odds ratio, ranging from 1.46 (95% confidence interval, 1.04–2.06) for those smoking <11 cigarettes per day to 5.66 (95% confidence interval, 2.14–14.95) for those smoking 40+ cigarettes per day.
The authors conclude that this study demonstrates a strong dose-response between the amount of cigarettes smoked and risk of IS in young men. Because the authors did not record the use of other tobacco products, one cannot exclude the possibility that concurrent use of these products could have affected the results. Similarly, the authors point out that they did not control for factors such as alcohol consumption and physical activity in the model, which may have resulted in unmeasured or residual confounding of the risk estimates. While complete cessation of smoking is the goal for patients, even reducing the number of cigarettes smoked may have beneficial health effects.