For people who are 55 and older, vitamin D deficiency may increase the likelihood of having trouble performing daily activities, according to research published in the Journal of Endocrinology and Metabolism.
Past research reports that vitamin D is associated with increased muscle mass, strength, and physical performance. However, few studies have looked at the link between vitamin D status and daily physical activity. The research that does address the topic produced mixed results.
Natasja cvan Schoor, PhD, of VU University Medical Center in Amsterdam, and colleagues analyzed data of two different cohorts from the Longitudinal Aging Study Amsterdam (LASA), a continuous study of Dutch individuals. The authors examined data from 725 participants with a mean age of 60, and about 1,200 participants from an older cohort (mean age 75).
The participants were asked about their ability to perform basic activities of daily living including: walking up and down stairs without resting, dressing and undressing, sitting and standing from chair, cutting their toenails, walking outside for 5 minutes without a break, and using personal or public transportation.
Fifty-six percent of the older group and 30% of the younger group reported at least one limitation at baseline. Fifteen percent in the older cohort and 6% in the younger cohort reported at least two additional limitations 3 years from baseline, and 20% and 8%, respectively, at 6 years.
Average vitamin D status was 21 ng/ml, with deficiency (<20 ng/ml) seen in about 50% of older individuals. The average level was 23 ng/ml in the younger group with 41% deficient.
The authors report that vitamin D deficiency was associated with an increased chance of having at least 1 functional limitation. Interestingly, the association was significant at 3 but not 6 years for the older cohort, and 6 but not 3 years for the younger group. Additional factors are most likely affecting the activity decline in the older group. With longer follow up, “vitamin D alone might not be discriminative anymore,” they explain.
The authors conclude:
“Although the current study is not designed to determine the direction of the relationship, the results of the longitudinal analyses, the known presence of vitamin D receptors on muscle cells, and the positive effects of vitamin D supplementation on muscle function at least suggest a potential positive effect of vitamin D on functional performance.”
The research was limited by the single vitamin D measurement of participants and the lack of information on diet and the use of supplements.
Neale T. Low vitamin D in 50s linked to disability. MedPage Today. July 17, 2013.