Adipokines and incident type 2 diabetes in a Canadian aborigine population - The Sandy Lake Health and Diabetes Project

OBJECTIVE - The aim of this study was to investigate associations of adiponectin, leptin, C-reactive protein (CRP), interleukin ((IL)-6, and serum amyloid A (SAA), individually or in combinations, with risk of incident type 2 diabetes in a Canadian Aborigine population. RESEARCH DESIGH AND METHODS - Of the 606 Sandy Lake Health and Diabetes Project cohort subjects who were free of diabetes at baseline, 540 (89. 1%) participated in 10-year follow-up assessments. Concentrations of fasting adiponectin, leptin, CRP, IL-6, SAA, and co-variates were measured at baseline. Fasting glucose and a 75-g oral glucose tolerance test were obtained at baseline and follow-up to determine incident type 2 diabetes, defined as clinically diagnosed type 2 diabetes or as fasting plasma glucose >= 7.0 mmol/l or 2-h postload plasma glucose >= 11.1 mmol/l at follow-up. RESULTS - Low adiponectin, high leptin, and low adiponectin-to-leptin ratio at baseline were associated with increased risk of incident type 2 diabetes after adjustment for age, sex, triglycerides, HDL cholesterol, hypertension, and impaired glucose tolerance (odds ratio 0.63 [95% Cl 0.48-0.83], 1.50 [1.02-2.21], and 0.54 [0.37-0.77], respectively). When the models were additionally adjusted for waist circumference or BMI, however, only low adiponectin remained significantly associated with increased incident diabetes (0.68 [0.51-0.90]). Combinations of leptin, CRP, IL-6, and/or SAA with adiponectin, assessed using either the ratio or joint effects, did not improve diabetes prediction. CONCLUSIONS - Low baseline adiponectin is associated with increased risk of incident type 2 diabetes independent of leptin, CRP, IL-6, SAA, and metabolic syndrome variables including obesity.