Effect of low-dose oral contraceptives on metabolic risk factors in African-American women

Context: The effect of oral contraceptive pill (OCP) use on cardiovascular risk in African-American women is unknown. Objective: Our objective was to examine in African-American women the effect of OCP use on insulin resistance, glucose intolerance, and triglycerides (TGs). Design: This was a cross-sectional study. Setting: The study was conducted at the National Institutes of Health Clinical Research Center. Participants: A total of 104 healthy nondiabetic African-American women [21 OCP users, 83 controls, age mean +/- SD, 34.7 +/- 7.6 yr, body mass index (BMI) 31 +/- 8.4 kg/m(2)] was included in the study. Interventions: Subjects had oral glucose tolerance tests, insulin-modified frequently sampled iv glucose tolerance tests, and fasting lipid profiles. Insulin resistance was determined by the insulin sensitivity index (S-I). Main Outcome Measures: Insulin resistance, glucose tolerance status, and TG levels were determined. Results: Fasting glucose did not differ between OCP users and controls (P = 0.27). In contrast, compared with controls, 2-h glucose (135 +/- 23 vs. 120 +/- 25 mg/dl; P = 0.01) and fasting TGs (73 +/- 31 vs. 57 +/- 27 mg/dl; P = 0.02) were higher in OCP users. OCP users tended to be more insulin resistant than controls (SI: 2.51 +/- 2.01 vs. 3.46 +/- 2.09; P = 0.09). Multiple regression analysis revealed that BMI, age, and OCP use were significant determinants of 2-h glucose (adjusted R-2 = 0.37; P < 0.001) and TG levels (adjusted R-2 = 0.21; P < 0.001). As BMI was a determinant of both 2-h glucose and TGs, participants were divided into nonobese and obese groups, and the analyses repeated. Among the nonobese women, the OCP users were more insulin resistant (S-I: 2.91 +/- 1.58 vs. 4.35 +/- 1.88; P = 0.03) and had a higher prevalence of glucose intolerance than controls (odds ratio 5.7; 95% confidence interval 1.4-24; P = 0.01). Conclusion: In African-American women, OCP use is associated with an increase in markers of cardiovascular risk manifested by increased insulin resistance, glucose intolerance, and elevated TGs.