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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)

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