Bone Mineral Density In Older Adults With T2DM After Exercise Training

Abstract

PURPOSE: To examine the effects of 9-months of exercise training on whole body and regional bone mineral density (BMD) in individuals with type II diabetes mellitus (T2DM). METHODS: Participants (N=191, men=71; age =57±8.y; BMI=34.4±5.8kg/m2; whole body BMD=1.19±0.13g/cm2; VO2peak =19.5±4.4ml/kg/min; mean±SD) from the HART-D study (NCT00458133) were randomized to aerobic (AER), resistance (RES), combined training (COMB) or a non-exercise control (CON). Compliant participants (>70% of sessions) with complete baseline and follow-up data for BMD (lumbar, thoracic, pelvis, and leg derived from whole body scans by DXA), peak oxygen uptake (VO2peak), isokinetic leg strength (peak torque at 60 deg/s), and anthropometry were included in this ancillary analysis. Associations between baseline BMD values (lumbar, thoracic, pelvis, leg and whole body BMD) were compared with age, sex, and baseline measures for VO2peak, isometric strength, and T2DM duration. Changes over 9-months were analyzed for group effects after adjusting for baseline. Changes in BMD were compared with age, sex, and changes in VO2peak and muscle strength. RESULTS: Baseline associations showed that age was inversely related to pelvis BMD (p=0.006, r=-0.20) and females had significantly lower thoracic, lumbar, and whole body BMD (p<0.001). VO2peak was correlated to leg (p<0.001, r=0.31) and whole body (p=0.02, r=0.17) BMD, and isokinetic leg strength was correlated to thoracic (p<0.001, r=0.26), pelvic (p<0.001, r=0.28), leg (p<0.001, r=0.46), and whole body (p<0.01, r=0.34) BMD. All groups increased whole body BMD with exercise training (P<0.05); however, no group effects were found for BMD changes after 9-months (p>0.10). Changes in pelvic BMD were found to be higher in females (p=0.04) than males and changes in VO2peak were inversely correlated with changes in thoracic BMD (p=.04, r=-.15). No significant effects were observed. CONCLUSION: Sex, aerobic fitness, and muscle strength had similar relationships with BMD in individuals with T2DM as typically found in the normal adult population. However, group changes after 9-months of exercise training, while increased, were not different from the changes in CON. Funding provided by the National Institutes of Health, R01-DK068298.