|SHEA, M - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|LOESER, RICHARD - University Of North Carolina|
|MCALINDON, TIMOTHY - Tufts University|
|HOUSTON, DENISE - Wake Forest University|
|KRITCHEVSKY, STEPHEN - Wake Forest University|
|BOOTH, SARAH - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
Submitted to: Arthritis Care and Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2017
Publication Date: 10/17/2017
Citation: Shea, M.K., Loeser, R.F., McAlindon, T.E., Houston, D.K., Kritchevsky, S.B., Booth, S.L. 2017. Sufficient vitamin K status combined with sufficient vitamin D status is associated with better lower extremity function: a prospective analysis of two knee osteoarthritis cohorts. Arthritis Care and Research. https://doi.org/10.1002/acr.23451.
Interpretive Summary: Knee osteoarthritis (OA) is the leading cause of lower-extremity disability in older adults. We investigated whether vitamin K nutritional status combined with vitamin D nutritional status was associated with lower-extremity function in two cohorts of adults who had or were at risk for knee OA because vitamin K- and vitamin D-dependent mechanisms are implicated in OA. In one cohort vitamin K and vitamin D status was estimated using diet questionnaires. In the other cohort vitamin K and vitamin D concentrations were measured in blood. Lower-extremity function was assessed using walking speed and other performance tests. In both studies, the participants who had the highest vitamin K status combined with the highest vitamin D status had faster walking speed at baseline and over 4-5 years of follow-up as compared to the participants who had high vitamin K status and low vitamin D status, high vitamin D status and low vitamin K status, and low vitamin K and low vitamin D status. These same participants also performed better on the other lower-extremity function tests. Our findings indicate that higher vitamin K status combined with higher vitamin D status could be beneficial to lower-extremity function in patients with knee OA but need to be confirmed in future studies.
Technical Abstract: Objective: Vitamins K and D are important for the function of vitamin K-dependent proteins in joint tissues. It is unclear if these nutrients are mutually important to functional outcomes related to knee osteoarthritis (OA). This study aimed to evaluate the association of vitamin K and D status with lower-extremity function in the Osteoarthritis Initiative (OAI) and Health Aging Body Composition Knee OA Sub-study (HABC). Methods: In the OAI (58% female, 61 +/- 9 years), baseline nutrient intake was estimated by food frequency questionnaire. Lower-extremity function was assessed using 20-meter gait speed and chair stand time. In HABC (60% female, 75 +/- 3 years), baseline nutrient status was measured using circulating vitamin K and 25(OH)D. Lower-extremity function was assessed using the short physical performance battery (SPPB) and 20-meter gait speed. The association of vitamin K and D status with lower-extremity function over 4-5 years was determined using multivariate mixed models. Results: OAI participants with the highest vitamin K intake and highest vitamin D intake combined had faster gait speed (p<0.001) and chair stand time (p=0.002) over follow-up compared to participants with the highest intakes of either nutrient alone and the lowest intakes of both. HABC participants with adequate circulating vitamin K (>/= 1.0 nmol/L) and adequate 25(OH)D (>/=50 nmol/L) combined had better SPPB scores and faster 20-meter gait speed over follow-up (both p<0.001). Conclusion: Higher vitamin K status combined with higher vitamin D status was associated with better lower-extremity function in two knee OA cohorts. These finding merit confirmation in vitamin K and D co-supplementation trials.