This systematic review demonstrates that vitamin D supplementation does not have a significant effect on muscle strength in vitamin D replete [adequate] adults. However, a limited number of studies demonstrate an increase in proximal muscle strength in adults with vitamin D deficiency. [The large close-to-body muscles supporting/connecting the hips/legs and shoulder/arms to the trunk – ‘pelvic girdle’ and ‘pectoral girdle’ muscles.]
Introduction: The purpose of this study is to systematically review the evidence on the effect of vitamin D supplementation on muscle strength in adults.
Methods: A comprehensive systematic database search was performed. Inclusion criteria included randomised controlled trials (RCTs) involving adult human participants. All forms and doses of vitamin D supplementation with or without calcium supplementation were included compared with placebo or standard care. Outcome measures included evaluation of strength. Outcomes were compared by calculating standardised mean difference (SMD) and 95% confidence intervals.
Results: Of 52 identified studies, 17 RCTs involving 5,072 participants met the inclusion criteria.
Meta-analysis showed no significant effect of vitamin D supplementation on grip strength (SMD -0.02, 95%CI -0.15,0.11) or proximal lower limb strength (SMD 0.1, 95%CI -0.01,0.22) in adults with 25(OH)D levels greater than 25 nmol/L.
Pooled data from two studies in vitamin D deficient participants (25(OH)D <25 nmol/L) demonstrated a large effect of vitamin D supplementation on hip muscle strength (SMD 3.52, 95%CI 2.18, 4.85).
Conclusion: Based on studies included in this systematic review, vitamin D supplementation does not have a significant effect on muscle strength in adults with baseline 25(OH)D greater than 25 nmol/L.
However, a limited number of studies demonstrate an increase in proximal muscle strength in adults with vitamin D deficiency.
Source: Osteoporosis International, Oct 6, 2010. PMID: 20924748, by Stockton KA, Mengersen K, Paratz JD, Kandiah D, Bennell KL. School of Medicine, University of Queensland, Brisbane, QLD, Australia. [Email: email@example.com]