Effects of non-supervised exercise interventions on bone mineral density in adult women: a systematic review and meta‑analysis

MINI ABSTRACT: Osteoporosis is a major health issue worldwide. This study analyzes the effects of non-supervised osteoporosis prevention programs on bone mineral density. Non-supervised exercise increases femoral neck and lumbar spine bone mineral density in adult women. Thus, it might be effective for preventing or treating osteoporosis or osteopenia in this population. INTRODUCTION: Osteoporosis is a major health issue worldwide. Social distancing measures due to COVID-19 have hindered the chances to take part in supervised osteoporosis prevention exercise programs. The purpose of the present study is to systematically review and meta-analyze the effects of non-supervised osteoporosis prevention exercise programs on bone mineral density (BMD) in adult women. METHODS: A comprehensive search of electronic databases (n = 7) was conducted including (a) prospective randomized controlled trials (RCTs) comparing at least one exercise group vs. a control group with sedentary lifestyle or sham exercises; (b) baseline and follow-up BMD values, or BMD changes from baseline, at any skeletal site; (c) women over 30 years old; and (d) non-supervised exercise programs only. Subgroup analyses were performed for menopausal status, intervention duration, type of exercise, and osteopenia/osteoporosis status. RESULTS: Ten studies were included (n = 668). Random effect analyses showed that unsupervised exercise had beneficial effects on lumbar spine (LS) BMD with standardized mean difference (SMD) = 0.40 (95% confidence interval (CI): 0.03–0.77), and femoral neck (FN) BMD with SMD = 0.51 (95% CI: 0.16–0.85). Unsupervised exercise increased LS (SMD = 0.73 (95% CI: 0.13–1.33)) and FN BMD (SMD = 0.85 (95% CI: 0.33–1.37)) in women with osteopenia/osteoporosis, but not in healthy counterparts. CONCLUSION: Non-supervised exercise improves FN and LS BMD in adult women. Beneficial effects of exercise on FN and LS BMD might be more pronounced in those with poor bone health compared with healthy counterparts. More RCTs prescribing non-supervised, osteogenic exercise are required in this population. It is necessary to investigate the efficacy of remote/assistive technologies for delivering and monitoring non-supervised exercise interventions. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00198-022-06357-3.