Vitamin D deficiency: subclinical and clinical consequences on musculoskeletal health.

Vitamin D is an important contributor to musculoskeletal health through its well-established key role in calcium and phosphorus metabolism. The association between vitamin D and various muscle disease outcomes appears promising. However, the role of vitamin D extends well beyond this traditionally labeled effect on muscle and bone health (eg, as a modulator of cell growth and immune function). While further research is needed (as there are still divergent opinions regarding these extraskeletal effects of vitamin D), strong, convincing evidence supports the benefits of vitamin D in promoting bone growth and maintenance, and this has been acknowledged in the recent Institute of Medicine report. However, it should be recognized that the research on vitamin D is still an emerging field, and it is beyond the scope of this paper to include more than a brief review of the published work.