Correlation between vitamin D and functional capacity, physical function among Japanese frail elderly living in the community

Abstract

Aim: To examine the distribution of 25-hydroxyvitamin D3 [25(OH)D] levels among the Japanese frail elderly, and to explore any association in these subjects between 25 (OH)D levels and functional capacity or physical performance. Methods: A cross-sectional survey was conducted in a town (latitude 36 degrees north) in June 2005 to September 2006. The 76 participants were community-dwelling elderly aged 65 years and over who attended a class for nursing care prevention. An interview was conducted based on a questionnaire. The serum levels of 25(OH)D, intact parathyroid hormone (iPTH) and calcium were measured. The following physical tests were performed: timed up and go (TUG), a 5-meter walk, functional reach, trunk flexion, and grip strength. Functional capacity and physical performance were compared between the subjects with 25(OH)D≧50nmol/L and those with 25(OH)D<50nmol/L. Results: About 52.6% experienced falls, 75.0% experienced stumbling or body sway more than once during the past year, and 20.0% were housebound. The mean 25(OH)D level (±SD) was 60.4 ± 13.6 nmol/L (range: 27.5-87.5). The ratio of the 25(OH)D level below 50.0nmol/L was significantly higher in the group of subjects who had lower mobility or body imbalance or were housebound. The risk factor for stumbling or body sway was 25(OH)D<50nmol/L (OR: 4.41,95%CI: 1.31-14.86). Conclusion: The prevalence of 25(OH)D<50nmol/L was 21% among Japanese frail elderly, and 25(OH)D deficiency is associated with lower mobility or body imbalance. It is suggested that the level of 25(OH)D should be needed over 50nmol/L for nursing care prevention in the frail elderly and that measurements of 25(OH)D for the frail elderly are needed.