Abstract
Vitamin K, known for its role in coagulation, is now implicated in osteoarthritis, the leading cause of mobility limitation in older age. We determined the association between vitamin K status and incident mobility limitation in 1098 older adults (mean(SD) age=75(3) years, 60% female, 45% black) over 6 years (median follow-up), using Cox proportional hazard regression, adjusted for demographics, lifestyle characteristics, and co-morbid conditions. Mobility limitation was based on two consecutive reports of severe difficulty walking one-quarter mile or up 10 steps without rest. Compared to those with <0.5 nM plasma vitamin K (n=212), those with 0.5–1.0 nM (n=398) and with ≥1.0 nM (n=488) plasma vitamin K were 27% less likely to develop mobility limitation [HRs(95%CIs): 0.5–1.0 nM = 0.73(0.58–0.92); ≥1.0 nM = 0.73(0.58–0.91); p=0.011]. These findings suggest vitamin K-dependent mechanisms may be involved in mobility limitation and a role for vitamin K in maintaining mobility in older age.