Objective. Examine the effects of exercise on femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD) in premenopausal women.Methods. Meta-analysis of randomized controlled exercise trials ≥24 weeks in premenopausal women. Standardized effect sizes (g) were calculated for each result and pooled using random-effects models,Zscore alpha values, 95% confidence intervals (CIs), and number needed to treat (NNT). Heterogeneity was examined usingQandI2. Moderator and predictor analyses using mixed-effects ANOVA and simple metaregression were conducted. Statistical significance was set atP≤0.05.Results. Statistically significant improvements were found for both FN (7g's, 466 participants,g=0.342, 95% CI=0.132, 0.553,P=0.001,Q=10.8,P=0.22,I2=25.7%,NNT=5) and LS (6g's, 402 participants,g=0.201, 95% CI=0.009, 0.394,P=0.04,Q=3.3,P=0.65,I2=0%,NNT=9) BMD. A trend for greater benefits in FN BMD was observed for studies published in countries other than the United States and for those who participated in home versus facility-based exercise. Statistically significant, or a trend for statistically significant, associations were observed for 7 different moderators and predictors, 6 for FN BMD and 1 for LS BMD.Conclusions. Exercise benefits FN and LS BMD in premenopausal women. The observed moderators and predictors deserve further investigation in well-designed randomized controlled trials.
Comparative effectiveness of different exercise on bone mineral density in postmenopausal women: a systematic review and network meta-analysis of randomized controlled trials
