Objectives: Vitamin K has bone and cartilage effects, and previously shown to be associated with radiographic osteoarthritis. We evaluated vitamin K’s effect on hand osteoarthritis in a randomised controlled trial.
Methods: This was an ancillary study to a randomised controlled trial assessing the effects of phylloquinone supplementation (vitamin K arm) versus placebo on bone loss and vascular calcification among older adults regardless of their vitamin K status. At the final 3-year study visit, we assessed the effects of vitamin K versus placebo on hand x-ray features of osteoarthritis using logistic regression and intention to treat, and also restricted analysis to the subgroup that had insufficient vitamin K concentrations at baseline.
Results: This ancillary study had 378 participants (193 in vitamin K arm, 185 in placebo arm). There were no effects of randomisation to vitamin K for radiographic osteoarthritis outcomes. Those with insufficient vitamin K at baseline who attained sufficient concentrations at follow-up had trends towards 47% less joint space narrowing (p = 0.02).
Conclusions: There was no overall effect of vitamin K on radiographic hand osteoarthritis. Subjects that were insufficient in vitamin K at baseline who attained sufficient concentrations at follow-up may have had a benefit in joint space narrowing. A clinical trial in those who are vitamin K insufficient may be warranted.
Trial registration number: NCT00183001.
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Funding: Arthritis Foundation Innovative Research Grant, and based upon work supported by the US Department of Agriculture, Agricultural Research Service under Cooperative Agreement No. 58-1950-7-707, and NIH (AG14759, HL696272 and AR47785). Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the authors and do not necessarily reflect the view of the US Department of Agriculture. TN was supported by the Arthritis Foundation Postdoctoral Fellowship Award and the Abbott Scholar Award in Rheumatology Research during the course of this work
Competing interests: None.
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