Cross-sectional study on different characteristics of physical activity as determinants of vitamin D status; inadequate in half of the population.

BACKGROUND/OBJECTIVES: Physical activity (PA) may have an impact on vitamin D status. The aim of the present study is to assess the contribution of different characteristics of PA (duration, intensity as estimated by energy expenditure, location) to vitamin D status.

SUBJECTS/METHODS: The study was conducted in 1255 community-dwelling older men and women of the Longitudinal Aging Study Amsterdam (LASA). Cross-sectional relationships between PA and serum 25-hydroxyvitamin D (25(OH)D) concentrations were examined.

RESULTS

Total PA, both indoor and outdoor PA, expressed in kcal/d was positively associated with 25(OH)D in women (P<0.05) but not in men. The total time spent on these activities was not associated. As compared with the lowest tertile, both men and women in the highest tertile of cycling activity (≈ 6.4 min/d or 34.7 kcal/d) had a ≥ 6 nmol/l higher 25(OH)D (P<0.05). For men and women in the highest tertile of gardening (≥ 8.6 min/d or 87.6 kcal/d), these levels were 14.2 nmol/l (P<0.001) and 5.8 nmol/l 25(OH)D (P<0.05), respectively. Walking showed no association.

CONCLUSIONS

Daily time spent on total PA is often included when studying the association between sum of PA and 25(OH)D, while our study showed that energy expenditure might be a better unit. Individual types of outdoor PA with a high intensity, such as gardening and cycling, were associated with 25(OH)D.