Objective: to investigate whether increased insulin resistance is associated with a reduced risk of weight gain among Hispanic and non-Hispanic white persons in Colorado.
Design: measurements were taken at baseline and after an average of 4.3 years.
Subjects: 789 normal glucose tolerant subjects 20 to 74 years of age were studied.
Measurements: fasting insulin levels were used as an indirect marker of insulin resistance.
Results: the average baseline body mass index (BMI) was 26.1 (+/- 3.6 s.d.) in men and 25.2 (+/- 4.4 s.d.) in women. The average weight change at follow-up was 0.8 kg (+/- 4.3 s.d.) in men and 1.3 kg (+/- 5.0) in women. A doubling in initial fasting insulin was associated with a reduced risk of gaining 5 kg (n = 134) and 10 kg (n = 24) of weight in logistic regression models (OR5kg = 0.76, 95% CI: 0.59, 0.99 and OR10kg = 0.61, 95% CI: 0.36, 1.02). Similarly, a doubling of initial fasting insulin was associated (P = 0.006) on average with a 6.3 kg less weight gain in linear regression models, independently of initial body weight, age, sex, ethnicity and BMI. The relation was consistently observed in men and women and in both ethnic groups.
Conclusion: higher initial fasting insulin decreases the risk of subsequent weight gain in both Hispanic and non-Hispanic white normal glucose tolerant individuals similar to Pima Indians. This appears to be a common biologic characteristic in moderate to low as well as high risk populations for NIDDM.