Routine vitamin D supplementation did not lower fracture rates in community-dwelling older adults.

In the Australian D-Health randomised trial, 21,000 community-dwelling older adults (age range, 60 to 85 years) received either 60,000 IU of vitamin D3 monthly or placebo for five years. Results published in 2022 showed no reduction in six-year mortality with vitamin D (NEJM JW Gen Med Mar 15 2022 and Lancet Diabetes Endocrinol 2022; 10: 120-128).

Now, the researchers present five-year fracture outcomes. No significant differences were noted between the vitamin D and placebo groups in total fractures (5.6% and 5.9%; p=0.32) or in nonvertebral, hip or major osteoporotic fractures. Mean 25-hydroxyvitamin D levels during the trial were about 75mmol/L in the placebo group and 112nmol/L in the supplemented group. However, about one-quarter of participants had estimated baseline levels below 50nmol/L and, even in that subgroup, vitamin D supplementation did not prevent fractures.

Comment: Given the results of this study and the large US VITAL study (NEJM JW Gen Med Aug 15 2022 and N Engl J Med 2022; 387: 299-309), we can say with confidence that five years of routine vitamin D supplementation does not lower fracture rates in healthy community-dwelling older adults. This issue of Lancet Diabetes and Endocrinology also includes an excellent review of vitamin D – with an emphasis on placebo-controlled clinical trials. The reviewers persuasively discuss the lack of evidence to support supplementation in most patient groups, and they call attention to some potential harms that are not widely appreciated by clinicians.

Allan S. Brett, MD, Clinical Professor of Medicine, University of Colorado School of Medicine, Aurora, USA.

Waterhouse M, et al. The effect of monthly vitamin D supplementation on fractures: a tertiary outcome from the population-based, double-blind, randomised, placebo-controlled D-Health trial. Lancet Diabetes Endocrinol 2023; 11: 324-332.

Gallagher JC, Rosen CJ. Vitamin D: 100 years of discoveries, yet controversy continues. Lancet Diabetes Endocrinol 2023; 11: 362-374.

This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine.