Low Serum Calcidiol Concentration in Older Adults with Reduced Muscular Function

OBJECTIVE: To examine the association between muscular function and the serum concentrations of 25‐hydroxyvitamin D (calcidiol) and 1,25‐dihydroxyvitamin D (calcitriol). DESIGN: A randomized population survey. Baseline measurements of serum calcidiol and calcitriol concentrations and assessment of muscular function (hand grip strength, ability to climb stairs, outdoor activity, and fall occurrence). SETTING: The Medical department, Aker University Hospital, Oslo, and subjects' homes. PARTICIPANTS: Two hundred forty‐six recently hospitalized older patients and 103 randomly selected older people living at home. MEASUREMENTS: Serum concentration of calcidiol and calcitriol in relation to muscle function. MAIN RESULTS: Reduced muscle function was associated with low calcidiol levels. In both the hospital group and the home group, calcidiol concentrations correlated positively to arm muscle strength (r = .22, P < .001, r = .37, P < .001), ability to climb stairs (r = .16, P < .05; r = ‐.42, P =