Basal state hyperinsulinemia in healthy normoglycemic adults heralds dysglycemia after more than two decades of follow up.

BACKGROUND: In a preliminary report, we found an association between hyperinsulinemia in the basal (fasting) state and the development of diabetes.
OBJECTIVES: The current analysis further explored the long term link between basal hyperinsulinemia and conversion to dysglycemia.
METHODS: This is a prospective study with up to 24 years of follow-up of 515 normoglycemic individuals (mean age at follow up = 70.3 ± 7.0; range 58-94) of an Israeli cohort. Fasting glucose and insulin were measured, and dysglycemia was defined as fasting glucose > 100 mg/dL.
RESULTS: At the end of the follow-up period, almost half had progressed to dysglycemia. Male sex and elevated baseline levels of basal insulin, body mass index, blood glucose and blood pressure each favoured progression to dysglycemia over the subsequent two decades. A multivariate logistic regression model identified basal hyperinsulinemia as the strongest predictor for progression to dysglycemia (odds ratio = 1.79; 95% confidence interval 1.12-2.88), while controlling for ethnicity, blood pressure, fasting glucose, male sex, body mass index and age.
CONCLUSIONS: Basal hyperinsulinemia in normoglycemic adults constitutes an independent risk factor for metabolic deterioration to dysglycemia over adulthood, and may help to identify apparently healthy subjects at increased risk for diabetes.