ORIGINAL ARTICLE Musculoskeletal Disorders DOI: 10.3346/jkms.2011.26.8.1093 • J Korean Med Sci 2011; 26: 1093-1098 Vitamin K Supplement Along with Vitamin D and Calcium Reduced Serum Concentration of Undercarboxylated Osteocalcin While Increasing Bone Mineral Density in Korean Postmenopausal Women over Sixty-Years-Old Sang Hyeon Je1, Nam-Seok Joo1, Beom-hee Choi2, Kwang-Min Kim1, Bom-Taeck Kim1, Sat-Byul Park1, Doo-Yeoun Cho1, Kyu-Nam Kim1 and Duck-Joo Lee1 1Department of Family Practice and Community Health, Ajou University School of Medicine, Suwon; 2Department of Family Medicine, CHA Biomedical Center, College of Medicine, CHA University, Seoul, Korea Received: 16 January 2011 Accepted: 12 May 2011 Address for Correspondence: Duck-Joo Lee, MD Department of Family Practice and Community Health, Ajou University School of Medicine, 164 Worldcup-ro, Youngtong-gu, Suwon 443-721, Korea Tel: +82.31-219-5309, Fax: +82.31-219-5218 E-mail: djleemd@msn.com There are inconsistent findings on the effects of vitamin K on bone mineral density (BMD) and undercarboxylated osteocalcin (UcOC). The present intervention study evaluated the effect in subjects over 60-yr-old. The vitamin K group (vitamin K + vitamin D + calcium supplement; 15 mg of vitamin K2 [menatetrenone] three times daily, 400 IU of vitamin D once a day, and 315 mg of calcium twice daily) and the control group (vitamin D + calcium supplement) were randomly assigned. During the six months of treatment, seventy eight women participated (38 in the vitamin K group and 40 in the control group) and 45 women completed the study. The baseline characteristics of study participants did not differ between the vitamin K and the control groups. In a per protocol analysis after 6 months, L3 bone mineral density has increased statistically significantly in the vitamin K group compared to the control group (0.01 ± 0.03 g/cm2 vs -0.008 ± 0.04 g/cm2, P = 0.049). UcOC concentration was also significantly decreased in the vitamin K group (-1.6 ± 1.6 ng/dL vs -0.4 ± 1.1 ng/dL, P = 0.008). In conclusion, addition of vitamin K to vitamin D and calcium supplements in the postmenopausal Korean women increase the L3 BMD and reduce the UcOC concentration. Key Words: Vitamin K; Undercarboxylated osteocalcin; Bone Mineral Density; Korean Women INTRODUCTION Health risk of osteoporosis is increasing in Korean women and there were many trials to reduce and prevent osteoporotic frac- ture risk (1, 2). Vitamin K plays a role in bone metabolism and may decrease the risk of fracture (3, 4). Vitamin K also acts syn- ergistically with Vitamin D on bone mineral density (BMD) and positively influences the balance of calcium, a key mineral in bone metabolism. As a cofactor for carboxylase activity, vitamin K facilitates the gamma-carboxylation of osteocalcin to increase the formation of bone (5). If the process of gamma-carboxylation is hindered by lack of vitamin K, the concentration of undercar- boxylated osteocalcin (UcOC), which has low affinity to hydroxy- apatite in bone, increases. An inverse relation between UcOC and BMD, and high serum UcOC levels in women in their 20 sec and 50 sec was recently reported (6). Since high UcOC level may make women in their 50 sec vulnerable to bone fracture, vitamin K supplementation may be worthwhile for women of this age group to improve BMD. However, the effects of vitamin K supplementation are contro- versial. Vitamin K supplementation provided protection against fractures, age related BMD decline, and osteoporosis in some studies (7-9), while other studies do not support a BMD benefit of vitamin K supplementation (10-14). Although studies exam- ining the effects of vitamin K supplementation on BMD or os- teoporosis have been conducted in many Asian countries (15- 18), the role of vitamin K in bone health in Korean postmeno- pausal women remains unclear. The present intervention study was designed to test the effects of vitamin K supplementation with vitamin D and calcium for 6 months on BMD and UcOC among the advanced postmeno- pausal Korean women over sixty years old. MATERIALS AND METHODS Subjects and study design We enrolled the advanced postmenopausal women over 60-yr- old, who did not want to take anti-resorptive agent such as bis- phosphonate. Therefore, postmenopausal women over sixty years old living in Seoul, Korea, who visited the Out Patients Clin- © 2011 The Korean Academy of Medical Sciences. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. pISSN 1011-8934 eISSN 1598-6357