Epidemiologic evidence has been collected in several population groups in the world demonstrating significant associations between hyperinsulinemia and hypertension. Patients with essential hypertension have been demonstrated to be insulin resistant by direct measurements by several investigators. It has been postulated, therefore that insulin plays a role in the pathogenesis of hypertension through a stimulation of the sympathetic nervous system, by promoting renal sodium retention, or by affecting cation transport. However, in the epidemiologic survey of Pima Indians no relationship between hypertension and serum insulin concentrations were found. To explore this further, the relationship between insulin resistance and blood pressure was studied in Pima Indians, Caucasians and Blacks. Insulin resistance is correlated with blood pressure in Caucasians but not in Pimas or Blacks.
