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

Presented as a poster at the 49th Annual Meeting and Exposition of the American Society of Hematology, Atlanta, GA, Dec. 8-11, 2007.
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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.

Section snippets

Materials and Methods

The study design has been described elsewhere.4, 5 For this report, cases were African American women 18-49 years of age with a recently diagnosed first episode of deep vein thrombosis and/or pulmonary embolism hospitalized at 1 of 2 university hospitals in Atlanta, GA. Cases were restricted to women without an underlying provocation for their VTE (arising in the absence of cancer; after surgery, a recent traumatic injury, or prolonged immobilization; during pregnancy; or in conjunction with

Results

The analysis includes 60 African American cases and 196 African American control subjects. In the entire case-control study, among 1867 potential cases sought for inclusion in the study, 61% participated. We mailed letters to 2956 potential control subjects of which we located 2095; 1942 of these subjects were eligible for inclusion as controls. Of these 1942 potential control subjects, 67% participated in the study.

The mean age of cases and controls was 36 and 38 years, respectively. The mean

Comment

This study indicates that current HC use is a risk factor for VTE among African Americans as it is among whites. The study findings also suggest that there may be synergy between HC use and SCT, in that the joint effect of the 2 exposures is considerably greater than the multiplicative effect of each (12.3 vs 2.6 × 1.9 = 4.9). However, because there are few current HC users with SCT, the OR for HC use among women with SCT is imprecise and, therefore, the difference in the ORs for subjects with

References (13)

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Dr Whitsett is currently affiliated with New York Blood Services and Mount Sinai School of Medicine, New York, NY.

Reprints not available from the authors.

This study was supported in part by a Grant from the Centers for Disease Control and Prevention through the Associations of Schools of Public Health/Centers for Disease Control and Prevention Cooperative Agreement mechanism.

Cite this article as: Austin H, Lally C, Benson JM, et al. Hormonal contraception, sickle cell trait, and risk for venous thromboembolism among African American women. Am J Obstet Gynecol 2009;200:620.e1-620.e3.

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