The Effect of Vitamin D Supplementation on Muscle Mass, Muscle Strength and Muscle Function in the Elderly: A Systematic Review and Meta-Analysis

Sarcopenia, the age-related loss of muscle mass, strength, and function is associated with falls and increased mortality. It is becoming a major public health concern due to its increase in prevalence, affecting over fifty million people worldwide. Due to the rising elderly population, this is expected to rise to over 200 million people by 2050. Mounting evidence supports the role of vitamin D in the stimulation of skeletal muscle fibre proliferation and differentiation. Therefore, vitamin D supplementation has the potential to prevent muscle loss and thus sarcopenia. Data from twenty-six randomised controlled trials including 6481 participants were summarised to investigate the effects of vitamin D supplementation on muscle mass, strength, and function in the form of balance, gait speed, and chair stand tests in the elderly population (≥60 years old). Results revealed that vitamin D supplementation had a significant positive effect on muscle mass (standardised mean difference (SMD) 0.27; 95% confidence intervals (CI) 0.12-0.42; P <0.001) and muscle strength (SMD 0.34; 95% CI -0.01 - 0.69; P=0.05). No significant effects were found for balance (SMD -0.06; 95% CI -0.19-0.08; P=0.40), gait speed (SMD 0.17; 95% CI -0.08–0.43; P=0.18), or chair stand tests (SMD 0.04; 95% CI -0.31–0.40; P=0.81) as markers for muscle function. These results suggest that vitamin D supplementation could have potential as a widely accessible cost effective intervention for reducing sarcopenia. However, further studies are required to evaluate optimum modalities such as dose and treatment duration.