Comparative effectiveness of different exercises on bone mineral density in postmenopausal women: a systematic review and network meta-analysis of randomized controlled trials

Objective: To compare and rank different exercise interventions on bone mineral density (BMD) in postmenopausal women. Data Sources and Study Selection: MEDLINE, EMBASE, CINAHL, AMED, the Cochrane Central Register of Controlled Trials (CENTRAL), Scopus and Web of Science were searched from database inception to January 2021 of randomized controlled studies investigating the effect of exercise more than six months on BMD in postmenopausal women. Data Extraction and Synthesis: Data at baseline and post intervention (or the change from baseline) were extracted. A Bayesian random-effects network meta-analysis was performed. Main Outcomes and Measures: The primary outcome was the change of BMD (at lumbar spine, femoral neck, and total hip) from baseline values. Effect size measures were mean differences with 95% credible intervals (CrIs). Results: We identified 3324 citations and included 66 studies with a total number of 4336 participants. Associated with BMD at lumbar spine (LS) improve were found for multicomponent exercise, resistance training, mind body exercise, lower impact exercise, high impact exercise, and whole body vibration. With regard to femoral neck (FN), only multicomponent exercise, whole body vibration, and mind body exercise were effective. As for total hip (TH), only multicomponent exercise, resistance training, and flexibility exercise were found to be beneficial. Moreover, No matter the age of postmenopausal women, and the duration of intervention (range between 6 to 18 months), some certain kinds of exercise could be performed to improve BMD at LS and FN. Conclusions and Relevance: This NMA confirms that exercise therapy has clear benefits on bone mineral density in postmenopausal women. It also shows that the magnitude of effect varies depending on the outcome of interest, the age of participants, and the duration of intervention. Clinicians might consult the ranking of the exercise intervention presented in this study, when designating an optimal, individualized exercise prescription to improve BMD.