Beta cell function, insulin resistance and plasma adiponectin concentrations are predictors for the change of postprandial glucose in non-diabetic subjects at risk for type 2 diabetes.
Insulin resistance, impaired insulin secretion, and low adiponectin levels have been shown to be predictors for type 2 diabetes. However, it is not yet clear whether these associations (1) are independent of changes in body weight, or (2) are valid for changes in glucose tolerance in the prediabetic state. Sixty-two non-diabetics (50 with normal glucose tolerance) aged 41 +/- 11 years, BMI 30.5 +/- 5.3 kg/m2 (mean +/- SD) were studied twice with a standard oral glucose tolerance test (oGTT, mean follow-up time 3.0 +/- 1.8 years (mean +/- SD) [range 0.5-6.5 years]). Insulin sensitivity and insulin secretion were estimated from oGTT using validated indices. Two-hour blood glucose during oGTT deteriorated over time (baseline 2 h glucose 6.32 +/- 0.21 VS. follow-up 2 h glucose 7.14 +/- 0.22 mM, p < 0.001) while the percentage body fat did not change (32.7 +/- 1.2 VS. 32.6 +/- 1.2%, p = 0.46). Follow-up 2 h blood glucose was predicted by adiponectin (p = 0.01), baseline insulin sensitivity (p = 0.02) and baseline insulin secretion relative to insulin sensitivity (p = 0.03) independent of sex, age, baseline 2 h blood glucose or change in percentage body fat. Our results suggest that low adiponectin levels, insulin resistance and low beta cell function predict the continuous deterioration of glucose tolerance in early prediabetic states, independent of changes in adiposity. Therefore, the early influence of these parameters should be the subject of future prevention programs to prevent deterioration of glucose tolerance.