Dose-response relationship between cigarette smoking and risk of ischemic stroke in young women

Background and Purpose-Although cigarette smoking is known to be a risk factor for ischemic stroke, there are few data on the dose-response relationship between smoking and stroke risk in a young ethnically diverse population. Methods-We used data from the Stroke Prevention in Young Women Study, a population-based case-control study of risk factors for ischemic stroke in women aged 15 to 49 years to examine the relationship between cigarette smoking and ischemic stroke. Historical data, including smoking history, was obtained through standardized interviews. Odds ratios (OR) were estimated using logistic regression. Cases (n = 466) were women with stroke in the greater Baltimore-Washington area, and controls (n = 604) were women free of a stroke history identified by random digit dialing. Results-After multivariable adjustment, the OR comparing current smokers to never smokers was 2.6 (P < 0.0001); no difference in stroke risk was observed between former smokers and never smokers. Adjusted OR increased with increasing number of cigarettes smoked per day (OR 2.2 for 1 to 10 cigs/d; 2.5 for 11 to 20 cigs/d; 4.3 for 21 to 39 cigs/d; 9.1 for 40 or more cigs/d). Conclusion-These results suggest a strong dose-response relationship between cigarette smoking and ischemic stroke risk in young women and reinforce the need for aggressive smoking cessation efforts in young adults.