Task Force advises against vitamin D, calcium for primary prevention of fractures in postmenopausal women

The U.S. Preventive Services Task Force recommended against taking daily supplementation of 400 IU or less of vitamin D₃ and 1,000 mg or less of calcium for the primary prevention of fractures in community-dwelling postmenopausal women.

This is a D recommendation (recommended against; there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefit). This recommendation does not apply to the treatment of persons with osteoporosis or vitamin D deficiency. The recommendation appears in the Feb. 26 Annals of Internal Medicine.

Also, the Task Force concluded that evidence is insufficient to assess the balance of the benefits and harms of daily supplementation with greater than 400 IU of vitamin D₃ and greater than 1,000 mg of calcium for the primary prevention of fractures (I statement).

To make the recommendation, the Task Force considered six randomized trials conducted in community-dwelling adults. No statistically significant reduction in fractures was observed in these studies (pooled relative risk, 0.89; 95% CI, 0.76 to 1.04).

The largest trial of fracture outcomes included in the meta-analysis was the Women's Health Initiative, which enrolled 36,282 healthy postmenopausal women ages 50 to 79. The intervention group received 400 IU of vitamin D₃ and 1,000 mg of calcium daily compared to a placebo group.

In the study, there was no statistically significant reduction in hip fracture (hazard ratio [HR], 0.88; 95% CI, 0.72 to 1.08) or total fractures (HR, 0.96; 95% CI, 0.91 to 1.02). However, the Task Force could not generalize the results of the Women's Health Initiative beyond the specific dose, preparation and population studied. Nearly 30% of study participants were already taking 500 mg or more of calcium daily before the start of the trial.

The Task Force has previously concluded in a separate recommendation that vitamin D supplementation is effective for community-dwelling adults aged 65 years or older who are at increased risk for falls (B recommendation; recommended. There is high certainty that the net benefit is moderate or that there is moderate certainty that the net benefit is moderate to substantial).

The Task Force also reported there is adequate evidence that supplementation with 400 IU or less of vitamin D₃ and 1,000 mg or less of calcium increases the incidence of renal stones, although the magnitude is small. The Women's Health Initiative noted a statistically increased incidence of renal stones in women taking supplemental vitamin D and calcium. One woman was diagnosed with a urinary tract stone for every 273 women who received supplementation over a 7-year follow-up period.