title: Vitamin K Status and Lower Extremity Function in Older Adults: The Health Aging and Body Composition Study.
abstract: While low vitamin K status has been associated with several chronic diseases that can lead to lower extremity disability, it is not known if low vitamin K status is associated with worse lower extremity function.
  
  
  
  Vitamin K status was measured according to plasma phylloquinone (vitamin K1) and dephosphorylated-uncarboxylated MGP (dp-ucMGP) in 1,089 community-dwelling older adults (mean ± SD age =74±3 years; 67% female). Lower extremity function was assessed using the short physical performance battery (SPPB), gait speed, and isokinetic leg strength. Linear regression and mixed models were used to determine the cross-sectional and longitudinal associations between vitamin K status and functional outcome measures.
  
  
  
  Cross-sectionally, higher plasma phylloquinone was associated with better SPPB scores and 20-m gait speed (p ≤ .05). After 4-5 years, those with ≥1.0nM plasma phylloquinone (the concentration achieved when recommended intakes are met) had better SPPB scores (p = .03) and 20-m gait speed (p < .05). Lower plasma dp-ucMGP (reflective of better vitamin K status) was associated with better SPPB scores and leg strength cross-sectionally (p ≤ .04), but not longitudinally. Neither measure of vitamin K status was associated with walking endurance or with the rate of decline in function.
  
  
  
  Older adults with higher vitamin K status had better physical performance scores at baseline, but data are less consistent longitudinally. Since lower extremity disability is a common consequence of multiple chronic diseases for which a role of vitamin K has been suggested, future studies are needed to determine if vitamin K supplementation could improve function in those with vitamin K insufficiency and clarify underlying mechanism(s).
authors.affiliation: Tufts University USDA Human Nutrition Research Center on Aging, Boston, Massachusetts. kyla.shea@tufts.edu.
authors.forename: M Kyla
authors.initials: MK
authors.lastname: Shea
authors.affiliation: Division of Rheumatology, Allergy and Immunology, University of North Carolina, Chapel Hill.
authors.forename: Richard F
authors.initials: RF
authors.lastname: Loeser
authors.affiliation: Division of Public Health Sciences, Wake Forest School of Medicine, Winston-Salem North Carolina.
authors.forename: Fang-Chi
authors.initials: FC
authors.lastname: Hsu
authors.affiliation: Tufts University USDA Human Nutrition Research Center on Aging, Boston, Massachusetts.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Booth
authors.affiliation: Department of Epidemiology and Biostatistics, University of California San Francisco.
authors.forename: Michael
authors.initials: M
authors.lastname: Nevitt
authors.affiliation: National Institute on Aging/NIH Baltimore, Maryland.
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Simonsick
authors.affiliation: Graduate School of Public Health, University of Pittsburgh, Pennsylvania.
authors.forename: Elsa S
authors.initials: ES
authors.lastname: Strotmeyer
authors.affiliation: VitaK, University of Maastricht, Netherlands.
authors.forename: Cees
authors.initials: C
authors.lastname: Vermeer
authors.affiliation: Sticht Center on Aging, Wake Forest School of Medicine, Winston-Salem, North Carolina.
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Kritchevsky
mesh_terms: D000368:Aged; D001823:Body Composition; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008137:Longitudinal Studies; D035002:Lower Extremity / Q000503:physiopathology*; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D010807:Physical Endurance; D014812:Vitamin K / Q000097:blood*; D000072797:Walking Speed / Q000502:physiology
chemical_list: D014812:Vitamin K
keywords: Nutrition; Physical function; Physical performance; Vitamin K