Physical activity, Vitamin D, and all-cause/cardiovascular mortality: a prospective study in older Chinese adults.

Background: Physical activity was associated with the risk of all-cause and cardiovascular mortality. However, little is known about older adults, especially those aged over 80 years.

Methods: 2863 older adults in the Chinese Longitudinal Healthy Longevity Survey (CLHLS) were enrolled. Physical activity score was used to evaluate the physical activity. Serum 25-hydroxyvitamin D and demographic characteristics were collected at baseline. We used multivariable-adjusted Cox regression models and stratified analysis to determine the association between physical activity, vitamin D and all-cause/cardiovascular mortality. Mediation analysis was performed to evaluate the mediating effect of vitamin D between physical activity and all-cause/cardiovascular mortality.

Results: The median age of this population was 87 years, and 70.27% were the oldest-old (age ≥ 80 years). We observed a tendency for a higher vitamin D concentration in participants with higher physical activity score levels. Both physical activity and vitamin D levels were inversely associated with all-cause and cardiovascular mortality in all participants. Between physical activity and all-cause/cardiovascular mortality, the mediation proportions of vitamin D were 7.76% (P < 0.001) and 4.13% (P < 0.001), respectively. The mediating effect of vitamin D remained all significant in various types of physical activities. Furthermore, vitamin D accounted for a greater mediating proportion in the physical activities of housework and raising domestic animals/pets.

Conclusions: Physical activity could reduce the risk of all-cause/cardiovascular mortality and was mediated by vitamin D in older Chinese adults.