To investigate associations of dietary vitamin K intake with changes in knee symptoms and structures in patients with knee OA.Method
Participants with symptomatic knee OA were enrolled (n=259) and followed up for 2?years (n=212). Baseline dietary vitamin K intake was calculated from a validated food frequency questionnaire. Knee symptoms were assessed by using the Western Ontario and McMaster University Index of osteoarthritis (WOMAC) scores. Knee cartilage defects, bone marrow lesions and effusion-synovitis volume were measured from MRI scans. Univariable and multivariable linear regressions were used for analyses.Results
Higher vitamin K intake quartile was significantly associated with greater decrease in total WOMAC score and dysfunction score over 24 months. The subgroup analyses showed in patients with severe baseline VAS pain, higher vitamin K intake quartile was associated with more improvement in all WOMAC scores. There were no overall significant associations between vitamin K intake and changes in MRI features. In sub-group analysis, vitamin K intake was negatively associated with changes in tibiofemoral, patellar and total cartilage defects in participants with severe baseline radiographic grade, and was negatively associated with change in total and patellar cartilage defects in participants with severe baseline VAS pain and in female patients.Conclusion
The association of higher vitamin K intake with decreased knee symptoms over 24 months in patients with knee OA suggests that clinical trials examining the effect of vitamin K supplementation for knee OA symptoms are warranted. Whether there is an effect on knee structure is unclear.
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