Relationships between undercarboxylated osteocalcin and vitamin K intakes, bone turnover, and bone mineral density in healthy women

Background Ea aims: Low vitamin K intakes and high levels of undercarboxylated osteocalcin (ucOC) are risk factors for hip fractures. However, the relationship between ucOC and vitamin K intakes, bone mineral density (BMD) and bone biochemical markers is not clarified. Methods: We enrolled 221 healthy women, and examined BMD, urinary type-I collagen cross-linked-N-telopeptide (uNTX), and nutrient intakes. BMD was measured at the lumbar spine and femoral neck. Results: Vitamin K intakes were significantly and negatively correlated with ucOC after adjustment for age, height, and body weight (r = -0.305, p < 0.0001). ucOC was negatively associated with lumbar BMD (r = -0.147, p < 0.05), but not femoral neck BMD (r = -0.099, p = 0.095) after adjustment for age, height, and body weight. In multiple regression analysis, even after adjustment for age, height, body weight, and vitamin K intake, a significant and positive correlation remained between ucOC and urinary NTX (r = 0.493, p < 0.0001). Moreover, in postmenopausal women, ucOC levels were positively correlated with urinary NIX, but not BMD. Conclusion: Dietary vitamin K intakes influence serum levels of ucOC in healthy women. Furthermore, ucOC may be linked to bone biochemical markers. (C) 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.