Cigarette smoking. A risk factor for cerebral infarction in young adults.

To assess the impact of cigarette smoking on stroke in young adults (15 to 45 years old), we compared smoking data from 181 patients with cerebral infarction with that of 307 control subjects matched for age, gender, geographic location, and hospital admission dates. While controlling for these matching variables and hypertension, an analysis based on a conditional logistic regression model indicated that a smoker was 1.6 times more likely to have a cerebral infarction than a non-smoker (95% confidence interval, 1.07 to 2.42). There was a cumulative dose effect with each additional pack-year causing a greater risk of having a cerebral infarction. In fact, after adjusting for all other risk factors, there was a significant quadratic component to the dose-response relationships, with the result that individuals with a larger number of pack-years were invariably the stroke patients. There was no significant difference in smoking status among the various subtypes of cerebral infarction (atherosclerotic, nonatherosclerotic vasculopathy, cardioembolic, hematologic related, undetermined). These data indicate that cigarette smoking is an important risk factor for cerebral infarction in young adults. Risk factor modification through cessation of smoking may reduce the risk of ischemic stroke in young adults.