Vitamin K supplementation and progression of coronary artery calcium in older men and women

Background: Coronary artery calcification (CAC) is an independent predictor of cardiovascular disease. A preventive role for vitaminK in CAC progression has been proposed on the basis of the properties of matrix Gla protein (MGP) as a vitamin K–dependent calcification inhibitor. Objective: The objective was to determine the effect of phylloqui-none (vitamin K1) supplementation on CAC progression in older men and women. Design: CAC was measured at baseline and after 3 y of follow-up in 388 healthy men and postmenopausal women; 200 received a mul-tivitamin with 500 lg phylloquinone/d (treatment), and 188 re-ceived a multivitamin alone (control). Results: In an intention-to-treat analysis, there was no difference in CAC progression between the phylloquinone group and the control group; themean (6SEM) changes inAgatston scoreswere 276 6 and 376 7, respectively. In a subgroup analysis of participants who were 85 % adherent to supplementation (n 367), there was less CAC progression in the phylloquinone group than in the control group (P 0.03). Of those with preexisting CAC (Agatston score. 10), those who received phylloquinone supplements had 6 % less progression than did those who received the multivitamin alone (P 0.04). Phyl-loquinone-associated decreases in CAC progression were indepen-dent of changes in serum MGP. MGP carboxylation status was not determined. Conclusions: Phylloquinone supplementation slows the progression of CAC in healthy older adults with preexisting CAC, independent of its effect on total MGP concentrations. Because our data are hypothesis-generating, further studies are warranted to clarify this mechanism. This trial was registered at clinicaltrials.gov as NCT00183001. Am J Clin Nutr 2009;89:1799–807