Association of Vitamin K Status Combined With Vitamin D Status and Lower-Extremity Function: A Prospective Analysis of Two Knee Osteoarthritis Cohorts

Arthritis Care Res (Hoboken). 2018 Aug;70(8):1150-1159. doi: 10.1002/acr.23451. Epub 2018 May 29.


Objective: Vitamins K and D are important for the function of vitamin K-dependent proteins in joint tissues. It is unclear whether these nutrients are mutually important to functional outcomes related to knee osteoarthritis (OA). We evaluated the association of vitamin K and D sufficiency with lower-extremity function in the Health, Aging and Body Composition knee OA substudy (Health ABC) and conducted a replication analysis in an independent cohort, the Osteoarthritis Initiative (OAI).

Methods: In Health ABC (60% female, mean ± SD age 75 ± 3 years) baseline nutrient status was measured using circulating vitamin K and 25-hydroxyvitamin D (25[OH]D). Lower-extremity function was assessed using the Short Physical Performance Battery (SPPB) and usual 20-meter gait speed. In the OAI (58% female, mean ± SD age 61 ± 9 years), baseline nutrient intake was estimated by food frequency questionnaire. Lower-extremity function was assessed using usual 20-meter gait speed and chair stand completion time. Multivariate mixed models were used to evaluate the association of vitamin K and D status and intake with lower-extremity function over 4-5 years.

Results: Health ABC participants with sufficient plasma vitamin K (≥1.0 nmoles/liter) and serum 25(OH)D (≥50 nmoles/liter) generally had better SPPB scores and faster usual gait speed over followup (P ≤ 0.002). In the OAI, sufficient vitamin K and vitamin D intake combined was associated with overall faster usual gait speed and chair stand completion time over followup (P ≤ 0.029).

Conclusion: Sufficient vitamin K status combined with sufficient vitamin D status was associated with better lower-extremity function in 2 knee OA cohorts. These findings merit confirmation in vitamin K and D co-supplementation trials.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Age Factors
  • Aged
  • Case-Control Studies
  • Dietary Supplements
  • Female
  • Geriatric Assessment / methods
  • Humans
  • Linear Models
  • Longitudinal Studies
  • Lower Extremity / physiopathology*
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Osteoarthritis, Knee / blood*
  • Osteoarthritis, Knee / physiopathology*
  • Prognosis
  • Prospective Studies
  • Risk Assessment
  • Severity of Illness Index
  • Sex Factors
  • Vitamin D / administration & dosage
  • Vitamin D / blood*
  • Vitamin K / administration & dosage
  • Vitamin K / blood*
  • Walking Speed*


  • Vitamin K
  • Vitamin D