title: Vitamin K, circulating cytokines, and bone mineral density in older men and women.
abstract: BACKGROUND
  Vitamin K modulates cytokines involved in bone turnover, including interleukin-6 (IL-6) and osteoprotegerin in vitro.
  
  
  OBJECTIVE
  The objective of this study was to assess 1) associations between measures of vitamin K status [plasma phylloquinone and serum percentage of undercarboxylated osteocalcin (%ucOC)] and IL-6, osteoprotegerin, and C-reactive protein (CRP) concentrations and 2) the effect of daily 500 mug phylloquinone supplementation for 3 y on cytokine concentrations.
  
  
  METHODS
  Concentrations of IL-6, osteoprotegerin, and CRP and bone mineral density (BMD) were measured at baseline and after 3 y of follow-up in 379 healthy men and women (60-81 y; 58.5% women) participating in a randomized trial that studied the effect of vitamin K supplementation on bone loss.
  
  
  RESULTS
  Cross-sectionally, plasma phylloquinone was inversely associated with IL-6 and CRP, whereas serum %ucOC was inversely associated with IL-6. Osteoprotegerin was associated positively with plasma phylloquinone and inversely with %ucOC. No differences were observed in the 3-y change in IL-6, osteoprotegerin, and CRP concentrations between participants who received phylloquinone supplementation and those who did not. Overall, no association was observed between the 3-y changes in circulating cytokines and BMD.
  
  
  CONCLUSIONS
  Poor vitamin K status was associated with high concentrations of cytokines involved in bone turnover, but vitamin K supplementation did not confer a decrease in cytokine concentrations. The healthy status of this cohort may explain a lack of effect of vitamin K supplementation on cytokine concentrations. This trial was registered with www.clinicaltrials.gov as NCT00183001.
authors.affiliation: US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.
authors.forename: M Kyla
authors.initials: MK
authors.lastname: Shea
authors.forename: Gerard E
authors.initials: GE
authors.lastname: Dallal
authors.forename: Bess
authors.initials: B
authors.lastname: Dawson-Hughes
authors.forename: José M
authors.initials: JM
authors.lastname: Ordovas
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: O'Donnell
authors.forename: Caren M
authors.initials: CM
authors.lastname: Gundberg
authors.forename: James W
authors.initials: JW
authors.lastname: Peterson
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Booth
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D015519:Bone Density / Q000187:drug effects* / Q000502:physiology*; D002097:C-Reactive Protein / Q000378:metabolism; D016207:Cytokines / Q000096:biosynthesis / Q000097:blood*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006304:Health Status; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis / Q000097:blood; D008297:Male; D008875:Middle Aged; D009752:Nutritional Status; D053244:Osteoprotegerin / Q000097:blood / Q000378:metabolism; D014812:Vitamin K / Q000097:blood* / Q000378:metabolism; D010837:Vitamin K 1 / Q000008:administration & dosage*
chemical_list: D016207:Cytokines; D015850:Interleukin-6; D053244:Osteoprotegerin; D014812:Vitamin K; D010837:Vitamin K 1; D002097:C-Reactive Protein