Fasting Insulin Level Is Positively Associated With Incidence of Hypertension Among American Young Adults

A 20-year follow-up study

  1. Ka He, MD, SCD1,2
  1. 1Department of Nutrition, Gillings School of Global Public Health and School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
  2. 2Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
  3. 3Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
  4. 4Division of Research, Kaiser Permanente Medical Care Program, Oakland, California
  5. 5Department of Biostatistics, Robert Stempel College of Public health and Social Work, Florida International University, Miami, Florida
  1. Corresponding author: Ka He, kahe{at}unc.edu.

Abstract

OBJECTIVE Although hyperinsulinemia, a surrogate of insulin resistance, may play a role in the pathogenesis of hypertension (HTN), the longitudinal association between fasting insulin level and HTN development is still controversial. We examined the relation between fasting insulin and incidence of HTN in a large prospective cohort.

RESEARCH DESIGN AND METHODS A prospective cohort of 3,413 Americans, aged 18–30 years, without HTN in 1985 (baseline) were enrolled. Six follow-ups were conducted in 1987, 1990, 1992, 1995, 2000, and 2005. Fasting insulin and glucose levels were assessed by a radioimmunoassay and hexokinase method, respectively. Cox proportional hazards models were used to calculate hazard ratios (HRs) and 95% CIs of incident HTN (defined as the initiation of antihypertensive medication, systolic blood pressure ≥140 mmHg, or diastolic blood pressure ≥90 mmHg).

RESULTS During the 20-year follow-up, 796 incident cases were identified. After adjustment for potential confounders, participants in the highest quartile of insulin levels had a significantly higher incidence of HTN (HR 1.85 [95% CI 1.42–2.40]; Ptrend < 0.001) compared with those in the lowest quartile. The positive association persisted in each sex/ethnicity/weight status subgroup. A similar dose-response relation was observed when insulin-to-glucose ratio or homeostatic model assessment of insulin resistance was used as exposure.

CONCLUSIONS Fasting serum insulin levels or hyperinsulinemia in young adulthood was positively associated with incidence of HTN later in life for both men and women, African Americans and Caucasians, and those with normal weight and overweight. Our findings suggested that fasting insulin ascertainment may help clinicians identify those at high risk of HTN.

  • Received December 15, 2011.
  • Accepted March 8, 2012.

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This Article

  1. Diabetes Care
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