A prospective study of the associations between 25-hydroxy-vitamin D, sarcopenia progression and physical activity in older adults

Objective Low 25-hydroxyvitamin D (25OHD) levels may be associated with both sarcopenia (the age-related decline in muscle mass and function) and low physical activity (PA). Our objective was to describe prospective associations between 25OHD, muscle parameters, and PA in community-dwelling older adults. Design Prospective, population-based study with a mean followup of 2Æ6 ± 0Æ4 years. Patients Six hundred and eighty-six community-dwelling older adults (49% women; mean ± SD 62 ± 7 years old). Measurements Appendicular lean mass percentage (%ALM) and body fat assessed by Dual-energy X-ray Absorptiometry, leg strength by dynamometer, leg muscle quality (LMQ), PA assessed by pedometer, self-reported sun exposure by questionnaire, and serum 25OHD measured by radioimmunoassay. Results Participants with 25OHD £50 nm had lower mean %ALM, leg strength, LMQ and PA (all P < 0Æ05). As a continuous function, baseline 25OHD was a positive independent predictor of change in leg strength (b = 5Æ74 kg, 95% CI 0Æ65, 10Æ82) and LMQ (b = 0Æ49 kg/kg, 95% CI 0Æ17, 0Æ82). Also, change in 25OHD was positively predicted by baseline %ALM (b = 2Æ03 pm/p.a., 95% CI 0Æ44, 3Æ62) leg strength (b = 0Æ30 pm/p.a., 95% CI 0Æ06, 0Æ53), LMQ (b = 4Æ48 pm/p.a., 95% CI 0Æ36, 8Æ61) and PA (b = 2Æ63 pm/ p.a., 95% CI 0Æ35, 4Æ92) after adjustment for sun exposure and body fat. Conclusions 25OHD may be important for the maintenance of muscle function, and higher skeletal muscle mass and function as well as general PA levels may also be beneficial for 25OHD status, in community-dwelling older adults.