Vitamin D supplements do not protect bone health, analysis finds

Unfortunately, the experts’ comments in the news article by Ingrid Torjesen1 about our recent systematic review2 on the effects of vitamin D on falls, fracture and bone density in adults are either incorrect or mistargeted.

Professor Clarke’s comments are wrong. He stated that the trials in our meta-analysis had too few participants, used an insufficient dose of vitamin D, and had an insufficient duration of treatment to warrant changing health recommendations. He suggested waiting for the results of ongoing trials. In fact, there are ample trial data to permit reliable conclusions. The trials on falls, hip fracture or total fracture in our review included more than 34,000 participants, and there were 3534 individuals with a fracture, 870 with a hip fracture, and 14139 who had a fall. Almost all the recent trials of falls or fracture in our review used a vitamin D dose of >800IU/day, and overall 52% of trials used such doses. 17 trials of falls and fractures lasted >12 months, and 8 trials with >33,000 participants followed people for 3-5y. Trial sequential analyses show that there is reliable evidence that vitamin D supplementation does not have clinically relevant beneficial effects on falls, total and hip fracture.

The large ongoing trials of vitamin D supplements are not targeting populations most likely to benefit from supplementation (eg those with 25-hydroxyvitamin D <25 nmol/L).3 Instead, they are studying cohorts with similar vitamin D status to populations in the existing trials, using similar study designs to the existing trials.3 In our review, the trial sequential analyses indicate that future similar trials are unlikely to alter conclusions drawn from existing evidence. Thus, there is no reason to defer drawing conclusions about vitamin D supplementation for these outcomes when there exists a reliable body of evidence that is unlikely to be altered by further trials.

Professor Martineau suggests that supplementing the entire UK population with vitamin D will prevent the most extreme complications of rickets. This comment is not relevant to our paper. Our systematic review deals with vitamin D supplementation of adults for musculoskeletal health and should not be used in the debate about prevention of rickets in children. As noted in the BMJ news story, we specifically stated in our paper that individuals at high risk of rickets and osteomalacia should receive vitamin D supplementation. Supplementing population groups, such as the adults studied in the trials in our review, who are recommended vitamin D supplementation to maintain or improve musculoskeletal health in many clinical guidelines, will not prevent rickets but will mean that vast numbers of individuals take vitamin D supplements for no benefit.

Ingrid Torjesen also incorrectly states the vitamin D dose from the Scientific Advisory Committee on Nutrition report and Public Health England’s guidance as 10mg/day. The correct dose is 10 mcg/day, one thousand times less.

1. Torjesen I. Vitamin D supplements do not protect bone health, analysis finds. BMJ 2018;363.
2. Bolland MJ, Grey A, Avenell A. Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis. Lancet Diabetes Endocrinol 2018.
3. Bolland MJ, Grey A, Avenell A. Assessment of research waste part 2: wrong study populations- an exemplar of baseline vitamin D status of participants in trials of vitamin D supplementation. BMC Med Res Methodol 2018;18(1):101.