Can Vitamin D Supplementation Reduce the Risk of Fracture in the Elderly? A Randomized Controlled Trial

Randomized controlled trials have shown that a combination of vitamin D and calcium can prevent fragility fractures in the elderly. Whether this effect is attributed to the combination of vitamin D and calcium or to one of these nutrients alone is not known. We studied if an intervention with 10 μg of vitamin D 3 per day could prevent hip fracture and other osteoporotic fractures in a double‐blinded randomized controlled trial. Residents from 51 nursing homes were allocated randomly to receive 5 ml of ordinary cod liver oil ( n = 569) or 5 ml of cod liver oil where vitamin D was removed ( n = 575). During the study period of 2 years, fractures and deaths were registered, and the principal analysis was performed on the intention‐to‐treat basis. Biochemical markers were measured at baseline and after 1 year in a subsample. Forty‐seven persons in the control group and 50 persons in the vitamin D group suffered a hip fracture. The corresponding figures for all nonvertebral fractures were 76 persons (control group) and 69 persons (vitamin D group). There was no difference in the incidence of hip fracture ( p = 0.66, log‐rank test), or in the incidence of all nonvertebral fractures ( p = 0.60, log‐rank test) in the vitamin D group compared with the control group. Compared with the control group, persons in the vitamin D group increased their serum 25‐hydroxyvitamin D concentration with 22 nmol/liter ( p = 0.001). In conclusion, we found that an intervention with 10 μg of vitamin D 3 alone produced no fracture‐preventing effect in a nursing home population of frail elderly people.