부산대학교 도서관

Introduction:While oral contraceptive (OC) use is generally safe, women at higher risk for vascular disease are advised to use alternative forms of contraception. Smoking, a prothrombotic factor, is a contraindication for OC use in women over age 35. ABO blood group, specifically the non-O blood types, has also been associated with thrombosis risk. We therefore hypothesized that the effects of smoking and OC use on stroke risk would be accentuated in women with non-O blood groups.Methods:Using data from the Genetics of Early Onset Stroke Study, we used 3 polymorphisms within the ABO locus to classify blood group type in women under age 50, including 347 cases and 383 controls. Logistic regression was used to assess the stroke risk of current OC use, defined as use within 30 days, adjusted for other risk factors, and stratified by O and non-O blood group type.Results:Of the 347 women with early-onset stroke, 45% had African ancestry, 51% had European ancestry, and 4% had other ancestry. The median age was 42 years. After adjusting for race, age, hypertension, diabetes, migraines and aura, and smoking status, the odds ratio (OR) for stroke for smoking alone and OC use alone were 3.0 (95% CI 2.1-4.2) and 3.7 (95% CI 1.7-8.4), respectively in this population. Blood group (O vs non-O) did not appreciably alter the magnitude of these associations. However, the joint risk of smoking and OC use was substantially higher in women with blood group non-O (OR = 9.5, 95% CI 3.2-34.9) vs in women with blood group O (OR=4.9, 95% CI 0.4-110.2).Conclusions:Our findings are consistent with the possibility that non-O type blood group confers an increased risk of early onset stroke among OC users who smoke. Further studies are needed to confirm or refute this possibility and to determine whether non-O blood type should be considered in assessing the risk of OC use.