Abnormal glucose tolerance in young male patients with nonalcoholic fatty liver disease

Abstract

Objective: The association of nonalcoholic fatty liver disease (NAFLD) with insulin resistance and metabolic syndrome has been documented for obese men and middle-aged men. This study was designed to determine the relationship between NAFLD and the oral glucose tolerance test (OGTT) to predict preclinical diabetes in nondiabetic young male patients (<30 years old).

Methods: A total of 75 male patients who had elevated liver enzymes and who were diagnosed with NAFLD were enrolled in this study. A standard 75 g OGTT was carried out on all patients. Impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were defined as a fasting plasma glucose (FPG) level > or =100 mg/dl but <126 mg/dl, and a 2-h post-load glucose on the OGTT of > or =140 mg/dl, but <200 mg/dl respectively.

Results: According to the OGTT results, 24 (32%) patients were diagnosed as having IGT and 12 (16%) patients were diagnosed as having diabetes. Among the 48 patients with normal fasting glucose, 18 (37.6%) patients showed abnormal glucose tolerance (15 had IGT and three had diabetes). The NAFLD patients with abnormal glucose tolerance showed significant differences in age, weight, body mass index, waist-hip ratio, alanine aminotransferase, total bilirubin, total cholesterol, low-density lipoprotein cholesterol, triglyceride, insulin, FPG and homeostasis model for insulin resistance (HOMA-IR). Multiple regression analysis showed that age, FPG and HOMA-IR were independent predictors of abnormal glucose tolerance.

Conclusions: Although the patients were young men, an OGTT should be recommended for NAFLD patients with elevated liver enzymes and IFG to predict the risk of type 2 diabetes.

Fig. 1

Time course of blood glucose levels during the oral glucose tolerance test (OGTT) between normal glucose tolerance (NGT) and impaired glucose tolerance/diabetic glucose tolerance. The mean glucose concentrations during the OGTT between the two groups were compared using repeated comparisons at different time points (0, 30, 60, 90 and 120 min). Data are presented as means with 95% confidence intervals. The differences of all time points (0, 30, 60, 90 and 120 min) were statistically significant respectively (P<0.05).