Exercise and bone mineral density in men: a meta-analysis.

The purpose of this study was to use the meta-analytic approach to examine the effects of exercise on bone mineral density (BMD) in men. A total of 26 effect sizes (ES) representing 225 subjects from 8 studies met the criteria for inclusion. When BMD sites assessed were specific to the sites loaded during exercise, increases of approximately 2.6% (2.1% in the exercisers and -0.5% in the controls) were found. These results were statistically significant (ES = 0.213, 95% bootstrap confidence interval = 0.007-0.452). Statistically significant ES changes were found for older (>31 yr) but not younger (<31 yr) adults, with differences between groups statistically significant (P = 0.04). Statistically significant changes were also observed at the femur, lumbar, and os calcis sites. The results of this study suggest that site-specific exercise may help improve and maintain BMD at the femur, lumbar, and os calcis sites in older men. However, the biological importance of the small changes observed for most outcomes, quality of studies, and limited data pool prevent us from forming any firm conclusion regarding the use of exercise for maintaining and/or improving BMD in men. Clearly, a need exists for additional studies.