The addition of vitamin D to exercise for bone health Original paper

In this meta-analysis of intervention studies, the addition of vitamin D supplementation to exercise interventions did not increase bone mineral density in comparison with exercise alone. These findings were based predominantly on cohorts with adequate vitamin D levels at baseline.

The effects of adding supplemental vitamin D to exercise interventions on lumbar spine and/or hip bone mineral density (BMD), compared to the effects of exercise alone.

A total of 560 participants (ages >50; 84% women, 16% men).

The participants in 5 included studies consisted of postmenopausal women (predominantly white).

The analysis included participants with osteopenia, osteoporosis, and overweight/obesity. All of the studies excluded individuals who were receiving pharmaceutical treatments that had effects on calcium or bone metabolism.

This meta-analysis included 3 randomized controlled trials and 2 nonrandomized controlled trials. A subgroup analysis was conducted to examine the role of calcium, which was supplemented in 3 studies, as well as the role of BMD measurement location (lumbar spine and hip)

All participants were inactive or abstained from comparable exercise prior to the interventions. The average baseline vitamin D levels ranged from 21 ng/mL to 36 ng/mL among the 4 studies with data, indicating adequate vitamin D levels (20–50 ng/mL is generally considered adequate).

The exercise interventions consisted of resistance training (3 studies) or aerobic exercises (2 studies) such as bicycling or walking with weighted vests. When attendance rates and exercise protocols were considered, the average training volume was 2 to 3 hours per week.

There were no improvements in lumbar spine or hip BMD with the addition of vitamin D to exercise, compared to exercise alone. These findings were unchanged in a sensitivity analysis that removed the study with the lowest dose of vitamin D, and no effect of vitamin D was observed in the subgroup analyses of measurement location and calcium cosupplementation.

These findings are based on a small number of studies, predominantly consisting of cohorts with adequate vitamin D levels at baseline. Therefore, these results may not be generalizable to individuals with insufficient or deficient vitamin D levels.