Vitamin K, circulating cytokines, and bone mineral density in older men and women.
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.
Shea
M Kyla
MK
US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA.
Dallal
Gerard E
GE
Dawson-Hughes
Bess
B
Ordovas
José M
JM
O'Donnell
Christopher J
CJ
Gundberg
Caren M
CM
Peterson
James W
JW
Booth
Sarah L
SL
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*
D016207:Cytokines; D015850:Interleukin-6; D053244:Osteoprotegerin; D014812:Vitamin K; D010837:Vitamin K 1; D002097:C-Reactive Protein