Background: Serum insulin-like growth factor (IGF-1) may have a role in the maintenance of glucose homeostasis. We examined the association between serum IGF-1 and diabetes mellitus in a representative sample of US adults.

Methods: Third National Health and Nutrition Examination Survey participants aged ≥18 years (n=5,511). Main outcome was the presence of diabetes mellitus (n = 387).

Results: Lower serum IGF-1 levels were positively associated with diabetes mellitus after adjusting for age, sex, race/ethnicity, education, smoking, alcohol intake, body mass index, hypertension, glomerular filtration rate and serum cholesterol. Compared to quartile 4 of IGF-1 (referent), the odds ratio [OR] (95% confidence interval) of diabetes associated with quartile 1 was 2.16 (1.24-3.76); p-trend=0.002. However, the observed association between IGF-1 and diabetes was present only in those <65 years (OR=3.05; p-trend=0.006) and disappeared in those ≥65 years (OR=0.51; p-trend=0.18); p-interaction=0.0056.

Conclusion: Low IGF-1 levels are associated with diabetes mellitus among young subjects.