Association of Physical Activity and Body Fatness with Vitamin D Deficiency in Older Adults

ABSTRACT

BACKGROUND: This study investigated the association between physical activity and body fatness with serum vitamin D level in older adults. METHODS: A total of 233 older adults (39 men and 194 women) aged older than 65 years were voluntarily recruited from a local community. Physical activity was monitored using a uniaxial accelerometer. Body fatness was measured using a standardized protocol. Subjects were classified as sufficient (>30 ng/mL), insufficient (20-29 ng/mL), or deficient (<20 ng/mL) based on serum vitamin D level. Pearson correlation analyses were used to calculate bivariate correlations between variables. Logistic regression was used to determine the odds ratio of serum vitamin D inadequacy. RESULTS: There were linear increases in physical activity parameters including daily steps (P<0.001), low-intensity physical activity (P<0.001), moderate-intensity physical activity (P<0.001), and high-intensity physical activity (P<0.001) and linear decreases in body fatness parameters such as body mass index (P=0.039) and waist circumference (P=0.020) across incremental vitamin D levels. Vitamin D level was positively associated with daily steps (P<0.001), low-intensity physical activity (P<0.001), moderate-intensity physical activity (P<0.001), and high-intensity physical activity (P<0.001) and negatively associated with body mass index (P=0.001), percentage body fat (P=0.005), and waist circumference (P=0.003). Compared to the active group (reference), the inactive group (P=0.001) had a significantly higher odd ratio for serum vitamin D deficiency even after adjusting for age and sex (P=0.002). CONCLUSION: The findings of this study suggest that physical activity and vitamin D supplementation should be promoted for healthy aging.