INSULIN-STIMULATED GLUCOSE-UTILIZATION AND BORDERLINE HYPERTENSION IN YOUNG-ADULT BLACKS

The purpose of this investigation was to determine whether there is a relation between impaired insulin-stimulated glucose utilization, or insulin resistance, and blood pressure (BP) in a young adult black population. Clinically well, young black men and women, including normotensive (BP<135/85 mm Hg, n=23) and borderline hypertensive (BP greater-than-or-equal-to 135/85 mm Hg, n=27) individuals, were studied. Each subject had an oral glucose tolerance test (OGTT) and underwent a euglycemic hyperinsulinemic clamp procedure. A two-way analysis of variance demonstrated a significantly greater fasting insulin plasma concentration (P<.02) and sum of insulin levels during the OGTT (P=.04) in the borderline hypertensive compared with normotensive subjects. In both BP groups, women had significantly higher fasting plasma insulin levels than men (P<.02 and P=.009). Body mass index was a significant covariate of the plasma insulin concentration. Data obtained from the clamp demonstrated significant insulin resistance in borderline hypertensive compared with normotensive subjects (4.69+/-0.50 versus 6.57+/-0.63 mg/kg per minute, P=.002). A stepwise multiple linear regression analysis demonstrated that there are significant multiple correlations of insulin resistance with body mass index, clamped insulin level, BP group, and systolic BP (multiple R=.7862, P <.001). Application of this analysis to the nonobese sample (n =33) found significant correlations of insulin resistance with sex, BP group, and systolic BP (multiple R=.6817, P<.001). These data indicate that insulin resistance is present in young adult blacks with only borderline hypertension, and there is a relation between insulin sensitivity and blood pressure independent of body mass index. Also detected are significant gender differences in insulin-stimulated glucose utilization.