Relation between vitamin D, physical performance, and disability in elderly persons

Abstract

Background. The aim of this study was to evaluate the relationships between vitamin D, functional status, and disability in a sample of elderly, community-dwelling subjects. Methods. Serum values of 25-hydroxyvitamin D (25[OH] D) and albumin were determined in all participants. Anthropometric measures were obtained, and body composition was assessed using dual-energy x-ray absorptiometry. Arm and leg isometric strength was tested. Reported disability was evaluated using a modified version of the Activities of Daily Living Scale and physical performance with the 6-minute walking test and two items of the Short Form 36 Health Survey Questionnaire (SF-36). Results. A significantly higher prevalence of hypovitaminosis D, defined as level of 25(OH)D < 37.5 nmol/l, was observed in women than in men (55.4% and 35.1%, respectively; p < .001). In women, 25(OH)D was significantly associated with muscular strength and levels of physical function as assessed by SF-36. After adjusting for body mass index, albumin, appendicular fat-free mass, and season, muscle strength was still significantly lower in women with hypovitaminosis D than in those without. Women with reported disability showed significantly lower 25(OH)D values than those without. No relationship between muscular strength, physical function, or reported disability and 25(OH)D was found in men. Conclusions. In community-dwelling elderly women, 25(OH)D is related to muscular function and reported disability. Because of the high prevalence of hypovitaminosis D in the elderly population, this association seems to be clinically relevant.