A Cochrane review included 18 randomized controlled trials. Aerobics, weight bearing and resistance exercises were all effective on the bone mineral density (BMD) of the spine. The WMD for the combined aerobics and weight bearing program on the spine was 1.79 (95% CI 0.58 to 3.01). The analyzed results showed walking to be effective on both BMD of the spine 1.31 (95% CI –0.03 to 2.65) and the hip 0.92 (95% CI 0.21 to 1.64). Aerobic exercise was effective in increasing BMD of the wrist 1.22 (95% CI 0.71 to 1.74).
Comment: The quality of evidence is downgraded by imprecise results (wide confidence intervals) and by inconsistency (heterogeneity in interventions and outcomes).