OBJECTIVE—To examine whether decreased serum levels of adiponectin are an independent risk factor for the progression to type 2 diabetes in a Japanese population.

RESEARCH DESIGN AND METHODS—The serum levels of adiponectin and tumor necrosis factor-α (TNF-α) at baseline (from 1995 to 1997) were evaluated in 1,792 individuals (1,023 women and 769 men, aged 58.5 ± 12.5 years) from a cohort population (n = 3,706) of the Funagata study. Glucose tolerance was evaluated at baseline and also at 5-year follow-up examinations (n = 978, follow-up rate, 54.6%) according to the 1985 World Health Organization criteria. The correlation of clinical traits with serum levels of adiponectin was examined. The association of the traits with the progression to type 2 diabetes at the 5-year follow-up was also examined.

RESULTS—Among the traits examined, the correlation with aging was highest (r = 0.312, P < 0.001). Eighteen subjects with normal glucose tolerance (NGT) developed diabetes, and 709 remained NGT at the 5-year follow-up examinations. The subjects who became diabetic had decreased serum levels of adiponectin (7.29 ± 2.35 vs. 9.13 ± 2.35 10 × log μg/ml, P = 0.009). Multiple logistic regression analysis with age, sex, waist-to-hip ratio, and 2-h plasma glucose as the variables revealed that serum adiponectin level (odds ratio [per 0.1 log μg/ml] 0.766, P = 0.029) was an independent risk factor for the progression to type 2 diabetes. The subjects whose serum levels of adiponectin were in the lowest tertile were 9.320 times (95% CI 1.046–83.1) more likely to develop diabetes than those in the highest tertile (P = 0.046).

CONCLUSIONS—Decreased serum adiponectin level is an independent risk factor for progression to type 2 diabetes.