Different forms of exercise, resistance exercise training, and aerobic exercise training did little to counterbalance the effects of weight loss on bone density loss in older adults with obesity, according to a study published in the Journal of Bone and Mineral Research.
Researchers of this randomized, controlled trial investigated the effects of weight loss alone (n=60), weight loss and resistance exercise training (n=60), and weight loss and aerobic exercise training (n=67) on bone health in older adults with obesity and cardiovascular disease and/or metabolic syndrome. For all 3 groups, a total weight loss goal was 7% to 10% of baseline weight. Resistance exercise training included 4 days per week of upper and lower body weight machines, and aerobic exercise training included 4 days per week on a walking program. Analysis included demographic records, accelerometry data, bone densitometry-acquired bone mineral density measurements, blood samples, and CT scans. Measurements were taken at baseline, 6 months into the intervention, 18 months into the intervention, and a 30-month follow-up.
Of the total participants, at baseline, the mean age was 66.9 years old (SD 4.8), average body mass index was 34.5 kg/m2 (SD 3.7), and 39% had osteopenia. The weight loss only group had a mean weight loss of -5.7 kg (SD -7.9 to -3.8), the weight loss plus resistance training group had a mean weight loss of -10.1 kg (SD -12.0 to -8.2), and the weight loss plus aerobic exercise training group had a mean weight loss of -9.9 kg (SD -11.8 to -7.9). Accelerometer data indicated an increase in moderate to vigorous physical activity in the weight loss plus resistance training group by 22 minutes per week (SD -14 to 58), and in the weight loss plus aerobic exercise training group by 218 minutes per week (SD 180-255), but the weight loss only group had a reduction of -8 minutes per week (SD -47 to 31).
There were no significant effects of treatment to either bone mineral density or biomarkers of bone turnover, but hip bone mineral density reduced by 2% over 18 months. Trends did suggest that the lumbar spine experienced more of a reduction in density with the weight loss plus aerobic exercise training group than the other two groups. At the 30-month follow-up, all groups regained weight, with the highest increase in the weight loss only group, at a weight reduction of -3.4 kg from baseline weight (SD -5.7 to -1.5). The intervention did significantly increase areal bone mineral density in the lumbar spine at 30 months in both the weight loss only and weight loss plus resistance training vs weight loss plus aerobic exercise training (both P ≤.01).
Future studies need to explore long-term effects of resistance training on hip bone loss and bone loss continuation even after weight gain.
Researchers conclude that resistance exercise training and aerobic exercise training did not prevent bone loss due to weight loss in older adults who were obese and had either or both cardiovascular disease or metabolic syndrome, but resistance exercise training may have some long-term hip bone health benefits.
This study was supported by the National Institutes of Health/National Heart, Lung and Blood Institute. Please refer to reference for a complete list of authors’ disclosures.
Beavers KM, Walkup MP, Weaver AA, et al. Effect of exercise modality during weight loss on bone health in older adults with obesity and cardiovascular disease or metabolic syndrome: a randomized controlled trial [published August 7, 2018]. J Bone Miner Res. doi: 10.1002/jbmr.3555