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Vitamin K and Mobility with Age

10/8/2019 4:37:20 PM
The population of adults over the age of 65 is expected to double by the year 2050, with mobility limitations becoming an increasing concern. Identifying modifiable risk factors for mobility limitations and disabilities could help reduce the burden that mobility problems pose to individuals and society.

Possible vitamin K and mobility connection

One hypothesized risk factor for mobility limitations is vitamin K status. Vitamin K acts as an enzymatic cofactor in the post-translational carboxylation of vitamin K-dependent proteins, some of which are involved in musculoskeletal function. Previous studies have found that low vitamin K status is associated with osteoarthritis, cardiovascular disease, and worse physical performance—all of which might influence mobility.

There is no standard definition of vitamin K deficiency based on biomarkers, but serum phylloquinone and plasma dephospho-uncarboxylated matrix Gla-protein (ucMGP) give some indication of vitamin K status. Serum phylloquinone approximates 1.0 nmol/L when the recommended adequate intake for vitamin K is met. Serum phylloquinone drops to less than 0.5 nmol/L when the dietary intake is less than half of what is recommended. Plasma ucMGP increases as vitamin K status declines.

Researchers conducted a prospective cohort study to evaluate the association between vitamin K status and incident mobility limitation or disability. Participants were enrolled in the Health, Aging, and Body Composition Study (Health ABC), a prospective study of more than 3000 adults who were between the ages of 70 and 79 at the time of enrollment. The current analysis relied on data from 1323 participants who had measurements of serum phylloquinone at baseline. Mobility was assessed every 6 months, for a mean of 6 years (for mobility limitation) or 10 years (for mobility disability).

Study links vitamin K status and mobility levels

Results showed that participants with plasma phylloquinone < 0.5 nmol/L were significantly more likely to develop mobility limitation or disability than those with levels ≥ 1.0 nmol/L (p ≤ .05). Adjustment for knee pain attenuated the association, but not completely. The association between plasma ucMGP and mobility disability was significant but nonlinear, and there was no association between ucMGP and mobility limitation.
 
Strengths of this study included the large sample size, the prospective design, and the ability to adjust for confounding factors (including age, race, body mass index, level of education, triglycerides, interleukin-6, cognitive function, healthy eating index, and smoking). Limitations included the availability of only single measurements of plasma phylloquinone and ucMGP and no way to determine mechanisms of action.
 
The study concludes that vitamin K may be involved in the disability process. If further research confirms this idea, vitamin K supplementation may present a new strategy for maintaining mobility in older age.
 
Reference
Shea MK, Kritchevsky SB, Loeser RF, Booth SL. Vitamin K status and mobility limitation and disability in older adults: The Health, Aging, and Body Composition Study. J Gerontol A Biol Sci Med Sci. 2019;