Hormonal contraception, sickle cell trait, and risk for venous thromboembolism among African American women

OBJECTIVE: We evaluated the effect of oral and other hormonal contraceptive (HC) use on venous thromboembolism risk among African American women and investigated whether the association was modified by the sickle cell trait. STUDY DESIGN: We report the findings of a case-control study that included 60 African American women with an idiopathic, first episode of venous thromboembolism and 196 African American controls. RESULTS: The odds of current HC use compared with noncurrent use contrasting cases and controls is 3.8 (95% confidence interval [CI], 1.7-8.1; P < .001). Among subjects with sickle cell trait, the odds ratio is higher (odds ratio [OR], 6.7; 95% CI, 1.0-43) than the odds ratio among subjects without sickle cell trait (OR, 2.6; 95% CI, 1.1-6.2), but the difference is not statistically significant. CONCLUSION: This study provides persuasive evidence that hormonal contraceptive use increases venous thromboembolism risk among African American women and that the increase in risk may be larger among women with sickle cell trait.