Objective: To examine the association between adiponectin, a known predictor of diabetes in Pima Indians, and markers of inflammation and endothelial function in nondiabetic subjects and to assess whether these markers predict later diabetes in a case-control study within a longitudinal health study in Pima Indians.
Research design and methods: Participants with normal glucose tolerance at baseline were selected. Case subjects (who later developed type 2 diabetes), and control subjects (n = 71 pairs) were matched for BMI, age, and sex. Adiponectin, C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor-alpha, phospholipase A2 (sPLA2), soluble E-selectin (SE-selectin), soluble intracellular adhesion molecule-1, soluble vascular adhesion molecule-1, and von Willebrand factor (vWF) were measured in baseline samples.
Results: Adiponectin was negatively correlated with CRP (r = -0.25, P < 0.05), IL-6 (r = -0.20, P < 0.05), sPLA2 (r = -0.22, P < 0.05), and SE-selectin (r = -0.20, P < 0.05). CRP and IL-6 did not predict diabetes. Only vWF predicted the development of diabetes (incidence rate ratio 0.67 for a 1-SD difference, 95% CI 0.41-1.00, P = 0.05), but this was not significant after adjustment for age, glucose, HbA(1c), waist circumference, and fasting insulin (hazard rate ratio 0.73, 95% CI 0.46-1.16, P = 0.18).
Conclusions: Adiponectin is negatively correlated with markers of inflammation in vivo. In case and control subjects matched for BMI, with the exception of vWF, none of the inflammatory markers predicted diabetes. Adiponectin may be the link between adiposity, inflammation, and type 2 diabetes.