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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #360886

Research Project: Nutrients, Aging, and Musculoskeletal Function

Location: Jean Mayer Human Nutrition Research Center On Aging

Title: Vitamin K status and mobility limitation and disability in older adults: the health, aging, and body composition study

Author
item SHEA, M. KYLA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University
item KRITCHEVSKY, STEVE - Wake Forest University
item LOESER, RICHARD - University Of North Carolina
item BOOTH, SARAH - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Journal of Gerontology Medical Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2019
Publication Date: 5/6/2019
Citation: Shea, M., Kritchevsky, S.B., Loeser, R.F., Booth, S.L. 2019. Vitamin K status and mobility limitation and disability in older adults: the health, aging, and body composition study. Journal of Gerontology Medical Science. https://doi.org/10.1093/gerona/glz108.
DOI: https://doi.org/10.1093/gerona/glz108

Interpretive Summary: We investigated whether vitamin K status was associated with mobility disability in older adults because previous studies found that people with vitamin K insufficiency were more likely to have osteoarthritis, and osteoarthritis is the leading cause of disability in older age. Vitamin K status was estimated using two blood measures: vitamin K concentrations and uncarboxylated matrix gla protein (ucMGP) concentrations. UcMGP is a measure of vitamin K function, and concentrations increase when vitamin K status is low. Mobility disability was defined as two consecutive reports obtained 6-months apart, of having a lot of difficulty or inability walking 1/4 mile or climbing 10 steps without resting. We found vitamin K status was associated with mobility disability differently in men and women. Men with the lowest circulating vitamin K concentrations were over 60% more likely to develop mobility disability over 10 years of follow-up. However, circulating ucMGP was not associated with mobility disability in men. In women, circulating vitamin K was not associated with mobility disability. However, circulating ucMGP was, in that women with circulating ucMGP in middle of the range were more likely to develop mobility disability compared to the women with the highest or lowest amounts. These results suggest vitamin K may be involved in the disability process, but more studies are needed to needed to confirm our findings and understand the sex difference we detected.

Technical Abstract: Background: Osteoarthritis is the leading cause of lower-extremity disability in older adults. Low vitamin K status has been associated with more osteoarthritis development and progression, but the association between vitamin K status and mobility disability is unknown. Therefore, we determined the association between vitamin K status and incident mobility disability in the Health, Aging, and Body Composition Study. Methods: Plasma phylloquinone (vitamin K1) was categorized as <0.5, 0.5-<1.0 and >/= 1.0 nmol/L (n=635 men, 688 women). Plasma ucMGP, which increases when vitamin K status is low, was categorized into sex-specific tertiles (n=319 men, 397 women). Mobility disability, defined as two consecutive semi-annual reports of having a lot of difficulty or inability walking 1/4 mile or climbing 10 steps without resting, was assessed over a median 10 years of follow-up. Sex-specific Cox proportional hazard models were used to evaluate the association between vitamin K status and mobility disability. Results: Men with plasma phylloquinone <0.5 nmol/L were more likely to develop mobility disability compared to men with >/= 1.0 nmol/L [HR(95%CI)=1.67(1.09-2.55)]. After adjustment for knee pain (symptomatic of knee osteoarthritis), the association was partially attenuated [HR(95%CI)=1.50(0.96-2.35)]. In women, plasma ucMGP was non-linearly associated with mobility disability [HR(95%CI), compared to tertile 1: tertile 2=2.19(1.43-3.36), tertile 3=1.10(0.67-1.78), fully-adjusted]. Plasma ucMGP was not associated with mobility disability in men and plasma phylloquinone was not associated with mobility disability in women. Conclusion: Our results suggest vitamin K may be involved in the disablement process. Future studies are needed to confirm our findings and clarify the sex difference we detected.