Effect of Low-Dose Oral Contraceptives on Metabolic Risk Factors in African-American Women

Abstract

The effect of oral contraceptive pill (OCP) use on cardiovascular risk in African-American women is unknown. Our objective was to examine in African-American women the effect of OCP use on insulin resistance, glucose intolerance, and triglycerides (TGs). This was a cross-sectional study. The study was conducted at the National Institutes of Health Clinical Research Center. 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. 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)). Insulin resistance, glucose tolerance status, and TG levels were determined. 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 (S(I): 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). 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.