title: Vitamin K intake and osteocalcin levels in women with and without aortic atherosclerosis: a population-based study.
abstract: Protein-bound gamma-carboxyglutamate (Gla) has been demonstrated in calcified atherosclerotic plaques. Vitamin K is required for the formation of Gla-residues. As the biological activity of Gla-proteins appears to be strictly dependent on the presence of the Gla-residues, vitamin K status may be an important factor in the development and progression of atherosclerotic calcifications. We studied the association of vitamin K status, as assessed by nutritional vitamin K intake and the measurements of two circulating immunoreactive osteocalcin (irOC) fractions, with aortic atherosclerosis in a population-based study of 113 postmenopausal women. Women with calcified lesions (n = 34) had a 42.9 micrograms lower mean age-adjusted dietary vitamin K intake/day (95% C.I. -6.6 to 92.5) than those without calcifications (n = 79). Atherosclerotic women had higher irOC levels with a low affinity for hydroxyapatite (irOCfree): age-adjusted difference of 0.32 ng/ml (95% C.I. 0.03 to 0.61). In addition, the high affinity irOC levels expressed as a percentage (hydroxyapatite binding capacity, HBC) were 5.12% (95% C.I. 1.32 to 8.92) lower in women with calcifications. Our study indicates that women with aortic atherosclerosis have an impaired vitamin K status as reflected by a lower nutritional vitamin K intake, an increased irOCfree level and a reduced HBC level. An impaired vitamin K status in subjects with atherosclerosis is compatible with the view that vitamin K or Gla-containing proteins are involved in the development of calcification of the vessel wall.
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000378:metabolism; D000368:Aged; D001012:Aorta, Abdominal; D001018:Aortic Diseases / Q000097:blood*; D001161:Arteriosclerosis / Q000097:blood*; D001824:Body Constitution; D015992:Body Mass Index; D002114:Calcinosis / Q000097:blood*; D002846:Chromatography, Affinity; D015331:Cohort Studies; D004032:Diet; D017886:Durapatite / Q000378:metabolism; D005260:Female; D006801:Humans; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood*; D014812:Vitamin K / Q000032:analysis*; D014813:Vitamin K Deficiency / Q000150:complications*
chemical_list: D015675:Osteocalcin; D014812:Vitamin K; D015055:1-Carboxyglutamic Acid; D017886:Durapatite