[Skip to Content]
[Skip to Content Landing]
Comment & Response
June 2018

Caution to Readers About Systematic Review on Vitamin K and Prevention of Fractures That Included Problematic Trials

Author Affiliations
  • 1York Trials Unit, Department of Health Sciences, University of York, York, England
JAMA Intern Med. 2018;178(6):863-864. doi:10.1001/jamainternmed.2018.1127

To the Editor On behalf of my coauthors, I write to alert readers about the following article, “Vitamin K and the Prevention of Fractures: Systematic Review and Meta-analysis of Randomized Controlled Trials.”1

In this systematic review and meta-analysis,1 we assessed whether oral vitamin K (phytonadione and menaquinone-4) supplementation was associated with a reduction in bone loss and prevention of fractures. We included 13 trials with data on bone loss, and 7 of these trials reported fracture data. We reported that all studies but 1 showed an association of phytonadione and menaquinone-4 with reduction of bone loss. All 7 trials that had reported data on fractures were Japanese and used menaquinone-4. We reported: “Pooling the 7 trials with fracture data in a meta-analysis, we found an odds ratio (OR) favoring menaquinone-4 of 0.40 (95% confidence interval [CI], 0.25-0.65) for vertebral fractures, an OR of 0.23 (95% CI, 0.12-0.47) for hip fractures, and an OR of 0.19 (95% CI, 0.11-0.35) for all nonvertebral fractures.”1(p1256) We concluded: “This systematic review suggests that supplementation with phytonadione and menaquinone-4 reduces bone loss.”1(p1256)

Limit 200 characters
Limit 25 characters
Conflicts of Interest Disclosure

Identify all potential conflicts of interest that might be relevant to your comment.

Conflicts of interest comprise financial interests, activities, and relationships within the past 3 years including but not limited to employment, affiliation, grants or funding, consultancies, honoraria or payment, speaker's bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued.

Err on the side of full disclosure.

If you have no conflicts of interest, check "No potential conflicts of interest" in the box below. The information will be posted with your response.

Limit 140 characters
Limit 3600 characters or approximately 600 words