Elevated fasting insulin predicts incident hypertension: the ARIC study

Objective The prospective association of insulin and hypertension has been under debate in the context of the development of the insulin resistance or multiple metabolic syndrome. We examined the predictive associations of fa sting serum insulin with incident hypertension occurring alone or as part o f the multiple metabolic syndrome. Design Analyses were restricted to 5221 middle-aged participants of the Ath erosclerosis Risk in Communities Study cohort who were free of component di sorders of the multiple metabolic syndrome (hypertension; diabetes; high tr iglycerides and/or low HDL cholesterol (dyslipidaemias)) at baseline. Outcome A total of 1018 individuals developed hypertension, 801 in the abse nce of components of the metabolic syndrome and 217 in combination with dia betes or dyslipidaemias, between 1987 and 1993, Results Elevated fasting insulin (top quartile versus lowest quartile) was associated with overall incident hypertension in European Americans [hazard rate ratio (HRR) 2.0, 95% confidence interval (CI) 1.7-2.43 but the result s were inconclusive in African Americans (HRR 1.3, 95% CI 0.9-1.8) after ad justment for age, gender and study centre. Among European Americans, body m ass index and abdominal girth only partly explained the observed associatio n. Elevated fasting insulin was more strongly predictive of hypertension oc curring as a component of the multiple metabolic syndrome (HRR 2.4, 95% CI 1.5-3.9) than of hypertension occurring alone (HRR 1.3, 95% CI 1.0-1.7) adj usting statistically for age, gender, study centre, body mass index and abd ominal girth. Conclusions The results are consistent with the concept of an aetiological heterogeneity for hypertension and may explain previously reported inconsis tent findings on the association of insulin with incident hypertension. I H ypertens 1999, 17:1169-1177 (C) Lippincott Williams & Wilkins.