Effects of Vitamin K on Lower-extremity Function in Adults With Osteoarthritis:

Not Applicable

Recruiting

Brief Summary: The overall goal of this pilot randomized trial is to obtain necessary prerequisite data to conduct a randomized controlled intervention to test the effect of vitamin K supplementation on knee osteoarthritis progression and related functional decline. To address critical parameters required to design this larger RCT, we will conduct a double-blind, 2-armed, parallel-group intervention study, with a placebo run-in, in which 50 adults with mild to moderate knee OA and low baseline vitamin K status will be randomly assigned to 1 mg phylloquinone/day or matching placebo, and treated for 6 months. Specifically, we will: (1) compare the effects of 1 mg/day phylloquinone vs. placebo on the non-functional circulating form of MGP; (2) estimate rates of recruitment and retention, follow-up rates and reasons for loss to follow-up, response rates to questionnaires, adherence/compliance rates, and potential for site differences; and (3) determine the responsiveness of the Osteoarthritis Research Society International (OARSI)-recommended performance-based tests of physical function in adults with low vitamin K status and mild to moderate knee osteoarthritis. We will also obtain preliminary data on the distribution of MGP genotype at two clinical sites for effect size generation.

Recruitment & Eligibility

Inclusion Criteria

Age ≥ 50 years
Male or post-menopausal female (no menses in the last year)
Plasma phylloquinone <1.0 nmol/L
Chronic knee discomfort based on affirmative response to the question "During the past 12 months, have you had pain, aching, or stiffness in or around your knee(s) on most days for at least one month?"
Kellgren-Lawrence (KL) grade 2-3 in at least one knee
Ability to understand study procedures and to comply with them for the entire length of the study
Ability to answer questions by phone
Ability to swallow capsules

Exclusion Criteria

KL grade 4 in at least one knee
Inability to walk
Cognitive impairment (based on a Montreal Cognitive Assessment Test score ≤ 17)
Widespread pain
Malabsorption disorders (e.g. advance liver disease, stage 4 or 5 chronic renal disease, Crohn's disease, celiac sprue)
Serious medical conditions or impairments that, in the view of the investigator, would obstruct study participation
Plan to permanently relocate from the greater Boston, MA or Chapel Hill NC areas during the trial period
Planned knee or hip arthroplasty during the study period
Undergoing cancer treatment
< 50 years old
Circulating phylloquinone ≥ 1.0 nmol/L
Warfarin (Jantoven) use
Use of other investigational drugs
Use of herbal, botanical or vitamin K supplements
Use of assistive walking devices

Arm && Interventions

Group	Intervention	Description
Placebo	Placebo	Participants receive daily placebo matching phylloquinone for 24 weeks
Vitamin K	Vitamin K	Participants receive 1 mg/d phylloquinone orally for 24 weeks

Primary Outcome Measures

Name	Time	Method
Plasma uncarboxylated matrix gla protein	24 weeks	Plasma uncarboxylated matrix gla protein is considered a functional indicator of vitamin K status. We will evaluate how it changes in response to 1 mg/d vitamin K supplementation in adults with low vitamin K status at baseline and with radiographic knee OA.

Secondary Outcome Measures

Name	Time	Method
Plasma phylloquinone	24 weeks	Circulating phylloquinone is considered a global indicator of vitamin K status. We will evaluate how it changes in response to 1 mg/d vitamin K supplementation in adults with low vitamin K status at baseline and with radiographic knee OA.

Locations (2): University of North Carolina Chapel Hill
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Chapel Hill, North Carolina, United States
Tufts University
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Boston, Massachusetts, United States

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