Context: Randomized control trials (RCT) of the effect of vitamin D/calcium supplementation on skeletal muscle strength have not shown promising effect in the elderly.
Objective: Our objective was to assess the effect of vitamin D and/or calcium on muscle strength in young adults with vitamin D deficiency.
Design and setting: We conducted a RCT using a factorial design at a tertiary-care center from September 2010 to April 2011.
Subjects: A total of 173 healthy females with mean age, body mass index, and 25-hydroxyvitamin D [25(OH)D] of 21.7 ± 4.4 yr, 20.8 ± 2.96 kg/m(2), and 9.3 ± 3.37 ng/ml, respectively, were block randomized to 1) double placebo, 2) calcium/placebo, 3) cholecalciferol/placebo, and 4) cholecalciferol/calcium for 6 months. Cholecalciferol was given at 60,000 IU/wk for 8 wk followed by 60,000 IU/fortnight. Elemental calcium was given in doses of 500 mg twice per day for 6 months.
Methods: Assessment included hand grip (primary outcome) and pinch grip strength, distance walked in 6 min, dyspnea score, quality of life by Short Form (36) Health Survey (SP-36), serum 25(OH)D, 1,25-dihydroxyvitamin D, and intact PTH.
Results: The serum 25(OH)D increased significantly to 29.9 ± 8.35 and 27.0 ± 9.54 ng/ml in two groups on cholecalciferol. The mean hand grip strength (19.4 ± 3.92, 21.1 ± 3.31, 20.6 ± 3.92, and 20.1 ± 4.00 kg) and its increase from baseline (0.3 ± 2.25, 0.3 ± 2.64, -0.3 ± 2.41, and 0.6 ± 2.30 kg) were comparable in four groups at 6 months. Quality of life, urinary calcium/creatinine ratio, and adverse effects were also comparable in groups.
Conclusion: Oral cholecalciferol/calcium supplementation in the dose/schedule used is effective and safe in increasing and maintaining serum 25(OH)D. However, this does not lead to improved skeletal muscle strength in young females.