Vitamin D and Associations with Walking Ability in Community- Dwelling Elderly Adults

Abstract

Epidemiological studies have suggested a positive association between vitamin D status and physical function. In order to improve our understanding of vitamin D and physical function, the present analysis investigated the associations between vitamin D status and walking ability in community-dwelling elderly adults, with particular consideration of body fatness and physical activity. This was a secondary, cross-sectional analysis, using baseline data from a randomized, controlled trial. The subjects were elderly adults living in a community (N=236, 73.7 ± 5.7 years, 58.2% female). BMI, body composition and serum 25-OH vitamin D were measured. Walking ability was assessed by the distance covered in a six-minute walk (6MWD). The dietary intake of vitamin D was estimated with a 3-day weighed food record, and physical activity was self-reported. The average serum 25-OH vitamin D levels mean was 67 ± 28 nmol/l. Serum 25-OH vitamin D correlated with self-reported physical activity in minutes per week (r=0.222, P=0.001). It also correlated with physical function in the 6MWD (r=0.264, P=0.037). Dietary vitamin D correlated with serum OH-25 vitamin D (r=0.297, P <0.001). Serum 25-OH vitamin D correlated negatively with BMI and fat mass (r= -0.165, P= 0.012 and r=-0.145, P=0.030). In this cross-sectional analysis we found associations between walking ability and vitamin D status in community-dwelling elder adults. However, these associations were not independent and were mostly explained by the confounding factors of BMI and self-reported physical activity.