OBJECTIVETo assess differences between the effects of aerobic and resistance training on HbA1c (primary outcome) and several metabolic risk factors in subjects with type 2 diabetes, and to identify predictors of exercise-induced metabolic improvement.RESEARCH DESIGN AND METHODSType 2 diabetic patients (n = 40) were randomly assigned to aerobic training or resistance training. Before and after 4 months of intervention, metabolic phenotypes (including HbA1c, glucose clamp–measured insulin sensitivity, and oral glucose tolerance test–assessed β-cell function), body composition by dual-energy X-ray absorptiometry, visceral (VAT) and subcutaneous (SAT) adipose tissue by magnetic resonance imaging, cardiorespiratory fitness, and muscular strength were measured.RESULTSAfter training, increase in peak oxygen consumption (VO2peak) was greater in the aerobic group (time-by-group interaction P = 0.045), whereas increase in strength was greater in the resistance group (time-by-group interaction P < 0.0001). HbA1c was similarly reduced in both groups (−0.40% [95% CI −0.61 to −0.18] vs. −0.35% [−0.59 to −0.10], respectively). Total and truncal fat, VAT, and SAT were also similarly reduced in both groups, whereas insulin sensitivity and lean limb mass were similarly increased. β-Cell function showed no significant changes. In multivariate analyses, improvement in HbA1c after training was independently predicted by baseline HbA1c and by changes in VO2peak and truncal fat.CONCLUSIONSResistance training, similarly to aerobic training, improves metabolic features and insulin sensitivity and reduces abdominal fat in type 2 diabetic patients. Changes after training in VO2peak and truncal fat may be primary determinants of exercise-induced metabolic improvement.

The profile of insulin secretion and the role of proinsulin processing across the spectrum of glucose tolerance in obese youth have not been studied. The aims of this study were to define the role of insulin secretion and proinsulin processing in glucose regulation in obese youth. We performed hyperglycemic clamps to assess insulin secretion, applying a model of glucose-stimulated insulin secretion to the glucose and C-peptide concentration data. Thirty obese youth with normal glucose tolerance (NGT), 22 with impaired glucose tolerance (IGT), and 10 with type 2 diabetes were studied. The three groups had comparable anthropometric measures and insulin sensitivity. The glucose sensitivity of first-phase secretion showed a significant stepwise decline from NGT to IGT and from IGT to type 2 diabetes. The glucose sensitivity of second-phase secretion was similar in NGT and IGT subjects yet was significantly lower in subjects with type 2 diabetes. Proinsulin-toinsulin ratios were comparable during first-and secondphase secretion between subjects with NGT and IGT and were significantly increased in type 2 diabetes. Obese youth with IGT have a significant defect in first-phase insulin secretion, while a defect in secondphase secretion and proinsulin processing is specific for type 2 diabetes in this age-group. Diabetes 54: 1735-1743, 2005

OBJECTIVEThere is no information about the role of nonalcoholic fatty liver disease (NAFLD) in predicting the development of chronic kidney disease (CKD) in type 1 diabetes. RESEARCH DESIGN AND METHODSWe studied 261 type 1 diabetic adults with preserved kidney function and with no macroalbuminuria at baseline, who were followed for a mean period of 5.2 years for the occurrence of incident CKD (defined as estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m 2 and/or macroalbuminuria). NAFLD was diagnosed by ultrasonography. RESULTSAt baseline, patients had a mean eGFR of 92 6 23 mL/min/1.73 m 2 ; 234 (89.7%) of them had normoalbuminuria and 27 (10.3%) microalbuminuria. NAFLD was present in 131 (50.2%) patients. During follow-up, 61 subjects developed incident CKD. NAFLD was associated with an increased risk of incident CKD (hazard ratio [HR] 2.85 [95% CI 1.59-5.10]; P < 0.001). Adjustments for age, sex, duration of diabetes, hypertension, A1C, and baseline eGFR did not appreciably attenuate this association (adjusted HR 2.03 [1.10-3.77], P < 0.01). Results remained unchanged after excluding those who had microalbuminuria at baseline (adjusted HR 1.85 [1.03-3.27]; P < 0.05). Addition of NAFLD to traditional risk factors for CKD significantly improved the discriminatory capability of the regression models for predicting CKD (e. CONCLUSIONSThis is the first study to demonstrate that NAFLD is strongly associated with an increased incidence of CKD. Measurement of NAFLD improves risk prediction for CKD, independently of traditional cardio-renal risk factors, in patients with type 1 diabetes.Nonalcoholic fatty liver disease (NAFLD) has reached epidemic proportions worldwide (1). Up to 30% of adults in the U.S. and Europe have NAFLD, and the prevalence of this disease is much higher in people with diabetes (1,2). Indeed, the prevalence of NAFLD on ultrasonography ranges from ;50 to 70% in patients with type 2 diabetes (3-5) and