A serum 25-hydroxyvitamin D level below 20 ng/mL was associated with physical decline.
Increasingly, researchers are focusing on possible extraskeletal manifestations of vitamin D deficiency (e.g., weakness and falls) in elderly populations. In the latest study, Dutch investigators evaluated the association between serum levels of 25-hydroxyvitamin D [25(OH)D] and physical performance scores (which assessed coordination, proximal muscle strength, and balance) in a population-based cohort of 1234 people aged 65 or older (mean age, 75).
Up to a threshold of 20 ng/mL, higher levels of 25(OH)D correlated with better physical performance scores after adjusting for potentially confounding variables such as age, sex, and number of chronic diseases. Beyond this threshold, physical performance was similar at all levels of 25(OH)D. Physical performance assessments were repeated in most participants 3 years later. People whose baseline 25(OH)D levels were below 20 ng/mL (about half the cohort) were twice as likely as those whose baseline levels exceeded 30 ng/mL to exhibit a 3-year decline in physical performance.
Comment: These results contribute to a body of evidence suggesting an association between vitamin D status and physical function in older people. The next step will be to prove (preferably through large controlled trials) that vitamin D supplementation improves physical performance and quality of life in elderly populations. In addition, consensus has not yet been reached on the optimal 25(OH)D level in this age group.
— Allan S. Brett, MD
Published in Journal Watch General Medicine June 14, 2007
Wicherts IS et al. Vitamin D status predicts physical performance and its decline in older persons. J Clin Endocrinol Metab 2007 Jun; 92:2058-65.