BACKGROUND Obesity exacerbates the age-related decline in physical function and causes frailty in older adults; however, the appropriate treatment for obese older adults is controversial. METHODS In this 1-year, randomized, controlled trial, we evaluated the independent and combined effects of weight loss and exercise in 107 adults who were 65 years of age or older and obese. Participants were randomly assigned to a control group, a weightmanagement (diet) group, an exercise group, or a weight-management-plus-exercise (diet–exercise) group. The primary outcome was the change in score on the modified Physical Performance Test. Secondary outcomes included other measures of frailty, body composition, bone mineral density, specific physical functions, and quality of life. RESULTS A total of 93 participants (87%) completed the study. In the intention-to-treat analysis, the score on the Physical Performance Test, in which higher scores indicate better physical status, increased more in the diet–exercise group than in the diet group or the exercise group (increases from baseline of 21% vs. 12% and 15%, respectively); the scores in all three of those groups increased more than the scores in the control group (in which the score increased by 1%) (P<0.001 for the between-group differences). Moreover, the peak oxygen consumption improved more in the diet–exercise group than in the diet group or the exercise group (increases of 17% vs. 10% and 8%, respectively; P<0.001); the score on the Functional Status Questionnaire, in which higher scores indicate better physical function, increased more in the diet–exercise group than in the diet group (increase of 10% vs. 4%, P<0.001). Body weight decreased by 10% in the diet group and by 9% in the diet–exercise group, but did not decrease in the exercise group or the control group (P<0.001). Lean body mass and bone mineral density at the hip decreased less in the diet–exercise group than in the diet group (reductions of 3% and 1%, respectively, in the diet–exercise group vs. reductions of 5% and 3%, respectively, in the diet group; P<0.05 for both comparisons). Strength, balance, and gait improved consistently in the diet–exercise group (P<0.05 for all comparisons). Adverse events included a small number of exercise-associated musculoskeletal injuries. CONCLUSIONS These findings suggest that a combination of weight loss and exercise provides greater improvement in physical function than either intervention alone.

Weight-loss therapy to improve health in obese older adults is controversial because it causes further bone loss. Therefore, it is recommended that weight-loss therapy should include an intervention to minimize bone loss such as exercise training (ET). The purpose of this study was to determine the independent and combined effects of weight loss and ET on bone metabolism in relation to bone mineral density (BMD) in obese older adults. One-hundred-seven older (age >65 yrs) obese (BMI ≥30 kg/m2) adults were randomly assigned to a control group, diet group, exercise group, and diet-exercise group for 1 year. Body weight decreased in the diet (−9.6%) and diet-exercise (−9.4%) groups, not in the exercise (−1%) and control (−0.2%) groups (between-group P<.001). However, despite comparable weight loss, bone loss at the total hip was relatively less in the diet-exercise group (−1.1%) than in the diet group (−2.6%), whereas BMD increased in the exercise group (1.5%) (between-group P<.001) Serum C-terminal telopeptide (CTX) and osteocalcin concentrations increased in the diet group (31% and 24%) while they decreased in the exercise group (−13% and −15%) (between-group P<.001). In contrast, similar to the control group, serum CTX and osteocalcin concentrations did not change in the diet-exercise group. Serum procollagen propeptide concentrations decreased in the exercise group (−15%) compared with the diet group (9%) (P=.04). Serum leptin and estradiol concentrations decreased in the diet (−25% and −15%) and diet-exercise (−38% and −13%) groups, not in the exercise and control groups (between-group P=.001). Multivariate analyses revealed that changes in lean body mass (β=.33), serum osteocalcin (β= −.24), and 1-RM strength (β=.23) were independent predictors of changes in hip BMD (all P<.05). In conclusion, the addition of ET to weight-loss therapy among obese older adults prevents weight-loss-induced increase in bone turnover and attenuates weight-loss-induced reduction in hip BMD despite weight-loss-induced decrease in bone-active hormones.

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