Changes in Body Fat Distribution and Fitness Are Associated With Changes in Hemoglobin A(1c) After 9 Months of Exercise Training: Results from the HART-D study

OBJECTIVE: To investigate the associations between changes in body composition and fitness after exercise training and changes in hemoglobin A(1c) (HbA(1c)) in individuals with type 2 diabetes. RESEARCH DESIGN AND METHODS: Participants (n = 201) were randomized to aerobic, resistance, or combined training for 9 months. HbA(1c), waist circumference, total and trunk fat mass, appendicular fat mass, lean body mass, isokinetic leg muscle strength, peak O(2) uptake, and estimated METs were assessed at baseline and follow-up. Change in HbA(1c) was evaluated across quartiles of change in body composition and fitness. RESULTS: Change in HbA(1c) was associated with changes in body weight (r = 0.13, P = 0.052), waist circumference (r = 0.17, P = 0.013), trunk fat mass (r = 0.19, P = 0.005), and estimated METs (r = −0.16, P = 0.023). There was a trend in change in HbA(1c) across quartiles of waist circumference (P = 0.011), trunk fat mass (P = 0.020), and estimated METs (P = 0.011). Participants with increased estimated METs and reduced trunk fat mass had greater odds of having reduced HbA(1c) after training (3.48, 1.46–8.31). Finally, participants with increased estimated METs and reduced waist circumference were 2.81 (1.13–6.98) times more likely to have reduced HbA(1c) and type 2 diabetes medication use than those without improved fitness and central adiposity. CONCLUSIONS: In patients with type 2 diabetes, a reduction in central adiposity and increase in fitness were the most prominent predictors of the change in HbA(1c) in response to exercise training.