The meta-analysis included data from 81 randomized controlled trials, totaling almost 54,000 participants, and concluded that vitamin D supplementation did not significantly impact fracture, falls, or bone mineral density (BMD).
Scientists from the University of Auckland in New Zealand and the University of Aberdeen in the UK said there is no longer any need for future research in this area, stating that additional trials are unlikely to change the results.
“[T]here is little justification for the use of vitamin D supplements to maintain or improve musculoskeletal health, and clinical guidelines should reflect these findings,” they wrote in the Lancet Diabetes & Endocrinology. “The clear exception to this is for the prevention or treatment of the rare conditions of rickets and osteomalacia, which can occur after a prolonged lack of exposure to sunshine that leads to 25OHD concentrations lower than 25 nmol/L.
“We believe there is no justification for more trials of vitamin D supplements with musculoskeletal outcomes because there is no longer equipoise about the effects of vitamin D on these outcomes.”
In response, Daniel Fabricant, PhD, president and CEO of the Natural Products Association, pointed out that numerous health organizations in the United States and around the world advocate for sufficient vitamin D intake, including the US FDA and guidelines in the Netherlands, Canada, and Australia.
“We were shocked when this study came out because of its total disregard for the wealth of scientific research and medical guidance in the US and around the world,” said Dr Fabricant. “Vitamin D is critical to supporting bone mineral density and a daily supplement at the advice of a doctor is an excellent way for people to get the right amount.”
Health organizations advocating for vitamin D
US FDA guidance for health claims on calcium, vitamin D, and osteoporosis: “Adequate calcium and vitamin D throughout life, as part of a well-balanced diet, may reduce the risk of osteoporosis” or “Adequate calcium and vitamin D throughout life, along with physical activity, may reduce the risk of osteoporosis in later life.” (21 CFR 101.72(f))
The 2011 Dutch Guideline on Osteoporosis and Fracture Prevention (CBO Guideline) advises that nursing home residents should take a vitamin D supplement (800 IU per day), and patients with osteoporosis should take a vitamin D supplement (800 IU per day).
Osteoporosis Canada states that experts recommend daily vitamin D supplements. High-risk individuals over 50 should receive 800-2,000 IU vitamin D per day.
The Australian guideline advises for women over 50 years of age a calcium intake of 1,300 mg per day and a vitamin D intake of 800 IU.
The new meta-analysis identified 81 randomized controlled trials with adults, which compared vitamin D with controls, placebo, or lower-dose vitamin D supplements. Forty-two trials investigated fractures, 37 investigated falls, and 41 investigated BMD. Almost half of the studies used vitamin D alone, 25% combined vitamin D with calcium, and one trial combined vitamin D with calcium and exercise.
The results indicated that vitamin D supplementation had no impact on all fracture types, hip fracture specifically, or falls. In addition, no significant differences between intervention groups were reported for bone mineral density at any skeletal sites were reported.
“Our findings suggest that vitamin D supplementation does not prevent fractures or falls, or have clinically meaningful effects on bone mineral density. There were no differences between the effects of higher and lower doses of vitamin D. There is little justification to use vitamin D supplements to maintain or improve musculoskeletal health. This conclusion should be reflected in clinical guidelines,” concluded the researchers.
“An important updated analysis on musculoskeletal health”
In an accompanying editorial in the same journal, J. Chris Gallagher, MD, from Creighton University Medical Center commends the authors of the paper, noting that they are leaders in the field of meta-analysis. “They have taken great care to analyze the data in every way possible, following PRISMA guidelines,” noted Dr Gallagher.
“The authors should be complimented on an important updated analysis on musculoskeletal health, but already I can hear the fervent supporters—what about the extra-skeletal benefits of vitamin D? Within 3 years, we might have that answer because there are approximately 100,000 participants currently enrolled in randomized, placebo-controlled trials of vitamin D supplementation. I look forward to those studies giving us the last word on vitamin D,” he added.
Lancet Diabetes & Endocrinology
Published online ahead of print, doi: 10.1016/S2213-8587(18)30265-1
“Effects of vitamin D supplementation on musculoskeletal health: a systematic review, meta-analysis, and trial sequential analysis”
Authors: M.J. Bolland