Circulating adiponectin levels and risk of type 2 diabetes in the Japanese

BACKGROUND: Adiponectin has anti-inflammatory and insulin-sensitizing properties. Prospective studies have consistently shown a lower risk of type 2 diabetes among those with higher circulating adiponectin levels. OBJECTIVE: We examined prospectively the association between serum adiponectin levels and type 2 diabetes risk among Japanese workers, taking visceral fat mass into account. SUBJECTS AND METHODS: Subjects were 4591 Japanese employees who attended a comprehensive health screening in 2008; had biochemical data including serum adiponectin; were free of diabetes at baseline; and received health screening in 2011. Multiple logistic regression analysis was used to examine the association between adiponectin and incidence of diabetes among overall subjects, as well as subgroups. Stratified analyses were carried out according to variables including visceral fat area (VFA). RESULTS: During 3 years of follow-up, 217 diabetic cases were newly identified. Of these, 87% had a prediabetes at baseline. Serum adiponectin level was significantly, inversely associated with incidence of diabetes, with odds ratios (95% confidence interval) adjusted for age, sex, family history, smoking, alcohol drinking, physical activity and body mass index (BMI) for the lowest through highest quartile of adiponectin of 1 (reference), 0.79 (0.55-1.12), 0.60 (0.41-0.88) and 0.40 (0.25-0.64), respectively (P-value for trend <0.01). This association was materially unchanged with adjustment for VFA instead of BMI. After further adjustment for both homeostasis model assessment of insulin resistance and hemoglobin A1c, however, the association became statistically nonsignificant (P-value for trend=0.18). Risk reduction associated with higher adiponectin levels was observed in both participants with and without obesity or insulin resistance at baseline. CONCLUSIONS: RESULTS suggest that higher levels of circulating adiponectin are associated with a lower risk of type 2 diabetes, independently of overall and intra-abdominal fat deposition, and that adiponectin may confer a benefit in both persons with and without insulin resistance.