Exercise training in obese older adults prevents increase in bone turnover and attenuates decrease in hip bone mineral density induced by weight loss despite decline in bone-active hormones

Abstract

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.

Effects of obesity treatments on bone mineral density, bone turnover and fracture risk in adults with overweight or obesity

“…In one of these meta-analyses, resistance training combined with high-impact weight bearing exercises was found to be better at enhancing BMD in postmenopausal women than resistance training alone [101]. Moreover exercise, particularly weight-bearing exercise, has been shown to reduce BMD losses during dietary restriction [93,103]. In addition, exercise-induced weight loss without dietary restriction does not appear to induce the significant decreases in BMD that have been observed with weight loss induced by dietary restriction alone [104].…”

Obesity and bone metabolism

“…These changes persist after partial weight regain independently of continued weight-bearing aerobic exercise [85]. However, in another randomized trial, older obese individuals who lost weight with a combination of diet and exercise rather than diet alone did not exhibit increases in bone turnover, and this was associated with an attenuation of the observed hip BMD loss [86]. Even though it seems that exercise is unlikely to be enough to prevent bone loss induced by weight loss, it seems that it attenuates the effects of weight loss and should therefore be encouraged alongside weight management strategies in order to minimize bone loss.…”

Does Diet-Induced Weight Loss Lead to Bone Loss in Overweight or Obese Adults? A Systematic Review and Meta-Analysis of Clinical Trials

“…Although we were able to categorize interventions according to the levels of prescribed energy intake, this did not take into account differences in macronutrient composition of the diets. A further limitation of this metaanalysis was that only 25% of the included studies involved comparison with a control group, (22,25,36,40,(45)(46)(47)73,74,80,82) as mentioned in the second paragraph of this Discussion.…”

“…Corresponding authors were contacted if any required data was not available from the publication or was published in a format different from that required for this meta-analysis. (20,(22)(23)(24)(25)28,(35)(36)(37)39,(42)(43)(44)(45)(46)(47)(69)(70)(71)73,74) For authors from whom we did not receive a response, (24,49,75) data for their publications were analyzed qualitatively rather than quantitatively.…”