Skeletal muscle strength in young Asian Indian females after vitamin D and calcium supplementation: a double-blind randomized controlled clinical trial.

Randomized, double-blind, placebo-controlled factorial trial in young, apparently healthy vitamin D-deficient Asian Indian women recruited at All India Institute of Medical Sciences, Delhi, India. Active intervention arms had 43 participants each; 173 women were randomized overall and 153 completed follow-up.

This double-blind factorial trial evaluated three oral active regimens over 6 months: calcium carbonate 500 mg elemental calcium twice daily, cholecalciferol 60,000 IU weekly for 8 weeks followed by 60,000 IU every 2 weeks for 4 months, or the combination of both regimens. Matching placebos were used as appropriate.

Oral calcium and/or cholecalciferol did not improve skeletal muscle strength, physical performance, or quality of life over 6 months. Handgrip strength showed no significant between-group difference (P=0.19), and pinch strength, 6-minute walk distance, dyspnea VAS, and SF-36 physical and mental component scores were also non-significant. Although supplementation increased vitamin D status and was generally well tolerated, hypercalciuria and hypercalcemia occurred across arms without significant group differences, including 2 cases of severe hypercalcemia.

Each active arm was modest in size (n=43), which limits power to detect small effects or uncommon harms. The sample was restricted to young vitamin D-deficient women from a single center in Delhi, reducing generalizability. Follow-up was only 6 months, and physical activity was not objectively measured during the trial.