Effects of Vitamin D and Calcium Supplementation on Falls: A Randomized Controlled Trial

Randomized controlled trial in frail elderly women living in long-stay geriatric care units in Switzerland. Participants were age 60 years or older and able to walk 3 m with or without a walking aid; the trial was conducted in Basel during winter, with the active arm followed for 12 weeks.

The active intervention was oral vitamin D plus calcium: two tablets per day, each containing 600 mg calcium carbonate and 400 IU cholecalciferol, taken twice daily with breakfast and dinner for 12 weeks. The total daily dose was 1200 mg calcium and 800 IU cholecalciferol, compared with calcium alone in the control arm.

Vitamin D plus calcium was superior to calcium alone for fall prevention over 12 weeks, reducing falls by 49% in adjusted Poisson regression (95% CI, 14-71%; p = 0.01). The number of fallers did not differ significantly between groups (RR 0.7; 95% CI, 0.3-1.5), but musculoskeletal function improved in the vitamin D plus calcium group (p = 0.0094). The combination also increased 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D and decreased iPTH, alkaline phosphatase, urinary DPD, and urinary NTX. Overall, the findings support vitamin D plus calcium as more effective than calcium alone for reducing falls and improving musculoskeletal and bone metabolism measures in this population.

The trial was small, short term, and limited to institutionalized elderly women in Switzerland, which restricts generalizability. Fall outcomes were assessed over only 12 weeks, and the number of fallers did not differ significantly despite fewer total falls. Safety findings were based on few events, with only mild constipation reported in the active group and no hypercalcemia observed.