Short-term Administration of Alphacalcidol is Associated with More Significant Improvement of Muscular Performance in Women with Vitamin D Deficiency Compared to Native Vitamin D

Positive relationships between muscle function and vitamin D (VD) status, defined by serum 25-hydroxy VD (25OHD) levels have been reported and muscle strength is generally improved with VD supplementation in deficient individuals. The effects of active VD analogs have been less studied. We aim to investigate the effect of short-term treatment with native VD (cholecalciferol) or alphacalcidol on the muscular function and physical performance in women with vitamin D deficiency. We analysed 178 women with VD deficiency, defined as serum 25-hydroxyVD-25OHD concentration below 30 ng/ml. We recorded the grip-strength and the results of the chair-rise test (CRT) and timed-up-and-go test (TUG). We randomised the patients to receive cholecalciferol 1 000 IU daily or alphacalcidol 1 μg daily, for 6 months. The mean baseline 25OHD concentration was 14.47±6.57 ng/ml. After treatment the serum 25OHD level rose to 20.85±8.88 ng/ml, significantly higher in cases supplemented with cholecalciferol (22.7±8.32 ng/ml) compared to those treated with alphacalcidol (13.5±7.29 ng/ml, p=0.000). After treatment, significant improvements of TUG and CRT test results (- 6.48 and-5.05% compared to baseline, respectively, p=0.000) and gripstrength (7.85% compared to baseline, p=0.000) occurred. The benefit was more significant in cases treated with alphacalcidol for gripstrength (p=0.001), TUG (p=0.002), CRT (p=0.033). After treatment, the gripstrength increased significantly more in patients with severe baseline VD deficiency. VD status improvement is associated with an increase in muscular performance in women with VD deficiency. Alphacalcidol exerts significantly better effects compared to cholecalciferol, and this can not be explained by a larger increase in serum 25OHD concentration.