INSULIN SENSITIVITY AND BLOOD-PRESSURE IN A BIETHNIC SAMPLE - THE MIAMI COMMUNITY-HEALTH STUDY

An association between blood pressure and insulin sensitivity among no rmotensive African-Americans has nor been demonstrated consistently in epidemiologic studies. Part of the discrepancy may be due to studying persons with profound obesity-an insulin-resistant state itself. The association between insulin-mediated glucose uptake (i.e., insulin sen sitivity) and blood pressure was examined among 25 nondiabetic African -American and 28 white non-Hispanic persons aged 25-44 years who range d from normal weight to obese, using the hyperinsulinemic euglycemic c lamp technique. In bivariate analyses, insulin sensitivity was inverse ly related to systolic (p < 0.01) and diastolic blood pressure (p = 0. 08) among African-American persons and to diastolic blood pressure amo ng white non-Hispanic subjects (p < 0.05). Covariate adjustment for ag e and sex had only a marginal effect on these results. When the data w ere pooled and further adjusted for ethnicity, insulin sensitivity rem ained significantly associated with both systolic and diastolic blood pressure (p < 0.01 for each). To consider the effect of obesity, body mass index (BMI) was divided at the sample median (26.5 kg/m(2)) and t he analyses were repeated within each stratum. Among those whose BMI w as below the median value, each increment in insulin sensitivity was a ssociated with a 2-mmHg decrease in systolic blood pressure (p = 0.02) . These results suggest that ethnicity was not a strong effect modifie r in this sample and indicated that insulin sensitivity was inversely related to blood pressure level in these normotensive African-American and white, non-Hispanic participants.