Objectives: The aim of this study was to evaluate the effects of early intensive insulin therapy on body fat distribution, lean body mass and β-cell function in patients with newly diagnosed type 2 diabetes.
Methods: Thirty-eight subjects with newly diagnosed type 2 diabetes participated in a 12-week course of intensive insulin therapy. Patients were administered a 75 g oral glucose tolerance test (OGTT), underwent measurement of visceral and subcutaneous adipose tissues (VAT and SAT) using computed tomography and appendicular skeletal muscle (ASM) mass was assessed using dual-energy X-ray absorptiometry.
Results: After intensive insulin therapy, fasting plasma glucose and HbA1c levels decreased. Homeostasis model assessment (HOMA)-B, the insulinogenic index, and the C-peptide-to-glucose area under the curve (AUC) ratio increased. The insulin sensitivity index and the glucose AUC decreased after 12 weeks. The body composition analysis revealed that the VAT and the ratio of VAT to SAT decreased, whereas body weight and total fat mass increased nonsignificantly. The ASM/weight and skeletal muscle mass index increased. The restoration of β-cell function, as identified by HOMA-B, the insulinogenic index, and the C-peptide-to-glucose AUC ratio, was correlated with the changes in VAT when controlled for age and gender. In multiple regression analyses, the decrease in VAT was shown to independently contribute to improved HbA1c over the study period, after adjusting for confounding factors.
Conclusions: These results suggest that a shift in fat distribution from visceral to subcutaneous fat after early intensive insulin therapy is associated with improvements in glycemic control and β-cell function in patients with newly diagnosed type 2 diabetes.
Keywords: Body fat distribution; Diabetes mellitus; Insulin; Type 2.