CIRCULATING LEVELS OF VITAMIN K1, MENAQUINONE-4, AND MENAQUINONE-7 IN HEALTHY ELDERLY JAPANESE WOMEN AND PATIENTS WITH VERTEBRAL FRACTURES AND PATIENTS WITH HIP FRACTURES

Recently, vitamin K has become increasingly of interest in the bone metabol-ism field because of its role as a cofactor in the carboxylation of osteocalcin. Although the role of osteocalcin is not clear, noncarboxylated osteocalcin is one risk factor in hip fractures. It has been reported that the circulating levels of vitamin K1 in osteoporotic patients were significantly lower than those of age-matched control subjects. In this study, we measured circulating levels of vitamin K1, menaquinone-4 (MK-4) and menaquinone-7 (MK-7) in 23 normal healthy women aged 52–93 years (mean ± SD: 80.1 ± 3.5), 13 female patients with vertebral fractures aged 66–93 years (80.3 ± 7.8) and 38 female patients with hip fractures aged 76–87 years (79.8 ± 9.2), (all Japanese), in order to make sure whether these vitamin K levels were different in these three groups. Serum circulating levels of MK-4 was undetectable in most subjects (only one out of 74). Appreciable numbers from these three groups had undetectable levels of MK-7...