INSULIN SENSITIVITY, LIPIDS, AND BLOOD-PRESSURE IN YOUNG AMERICAN BLACKS

The purpose of this study was to determine whether insulin resistance was linked with alterations in plasma lipids in adult young blacks wit h borderline hypertension. Ninety-four American blacks participated (4 6 men, 48 women, age range 28 to 33 years). Within this group of 94 su bjects, there were 60 normotensive (Nt) subjects and 36 subjects with borderline hypertension (BHt), defined as blood pressure > 135/85 mm H g. None of the subjects were diabetic or receiving antihypertension me dication. All participants had blood pressure and anthropometric measu rements, a fasting lipid profile, an oral glucose tolerance test, and a euglycemic hyperinsulinemic clamp. Insulin-stimulated glucose utiliz ation (M), determined by insulin clamp, was significantly lower in the BHt subjects compared with the Nt subjects (men, Nt 6.91 +/- 0.62 ver sus BHt 5.54 +/- 0.65; women, Nt 5.97 +/- 0.47 versus BHt 3.79 +/- 0.3 8 mg . kg(-1). min(-1), P = .006). When M was corrected for adiposity and expressed in milligrams per kilogram of fat free mass (M', the dif ference between Nt and BHt remained significant (P = .006). There was a significant correlation of M' with systolic blood pressure (r = -.39 3, P < .0001), HDL-C (r = .382, P < .0001), triglyceride level (r = -. 308, P < .001), apolipoprotein A-I (r = .190, P = .033), and apolipopr otein B (r = -.277, P = .004). When all lipid variables were entered i n a stepwise multiple linear regression analysis, HDL-C emerged as the most significant lipid component in the model for insulin resistance. These data suggest that in American blacks with mild hypertension, th e risk for cardiovascular disease may be augmented in the presence of insulin resistance.