BACKGROUND The relationships between insulin level and indexes of insulin resistance (IR) to predict incident hypertension have been explored only in cross-sectional or prospective studies with small numbers of patients. We investigated whether plasma insulin concentration and the homeostasis model assessment of insulin resistance (HOMA(IR)) are associated with the onset of hypertension in a population of apparently healthy and relatively lean Korean adults.

METHODS We selected 10,894 of 15,638 subjects who were normotensive at baseline during general health status evaluations in 2003 and 2008. The baseline and follow-up examinations included analyses of fasting glucose, insulin level, and lipid profile. Alcohol consumption, smoking status, exercise habits, and education level were also evaluated using a standard questionnaire.

RESULTS Of the 10,894 subjects, hypertension developed in 881 (8.1%) during the ensuing 5 years. Incident hypertension was more common among older subjects than it was in younger subjects and was associated with a high baseline body mass index (BMI). In multivariable logistic models, elevated serum insulin, and HOMA(IR) were associated with an increased risk of incident hypertension in both sexes. In a multivariable analysis using quartiles of insulin and HOMA(IR), the odds ratio (OR) for incident hypertension was the highest in the highest quartile of insulin and HOMA(IR). The highest quartile of insulin and HOMA(IR) was associated with a 1.5-1.7 times increased risk of incident hypertension.

CONCLUSIONS This 5-year follow-up study provides evidence that both a high circulating insulin level and HOMA(IR) are significant risk factors for the development of hypertension in a relatively lean and healthy population.