Background: Cardiovascular disease remains the leading cause of mortality and is worldwide directly re-sponsible for approximately 12 million deaths and 20％ of total mortality.1 Calcification of the conduit arteries is an independent risk factor for myocardial infarction, stroke and cardiovascular death.2 Vascular smooth muscle cells synthesize a small secretory protein (11 kD), which contains five γ-carboxyglutamate (Gla) amino-acids and which was therefore named matrix Gla protein (MGP).3 Activation of MGP requires two posttranslational modifications:γ-glutamate carboxylation in a vitamin K dependent manner and serine phosphorylation.Carboxylated MGP is a potent inhibitor of arterial calcification.In the presence of vitamin K deficiency, MGP is partly synthesized in a nonphosphorylated and uncarboxylated form (dp-ucMGP).The risk associated with dp-ucMGP in the population is unknown.