Background:In the past two decades, Vitamin K has been receiving more attention due to its role in bone health and metabolism. The bone mineral density does not remain steady with age, particularly declining after menopause.Objective: This study is aimed to investigate the relationship between bone mineral density and serum vitamin K1 levels in post-menopausal women, and to evaluate serum vitamin K1 levels as a potential biomarker for postmenopausal osteoporosis.Methods:Serum levels of vitamin k1 were measured in 23 postmenopausal osteoporotic women, and in 15 postmenopausal healthy control women using a standardized Enzyme-Linked Immune Sorbent Assay (ELISA) kit. Bone mineral density BMD was assessed at the lumbar spine.Results:The mean serum vitamin k1 level was significantly lower in the postmenopausal osteoporotic women group than in the normal control group (mean=0.794 vs3.61ng/ml, P< 0.0001), and serum vitamin k1 concentration was positively correlated with lumbar spine BMD among postmenopausal osteoporotic women (R=0.533, p = 0.009), and in postmenopausal healthy control (R=0.563, p = 0.02).Diagnostic sensitivity and specificity of vitamin k1 for osteoporosis were 90% and 98%, respectively (cut-off value: 0.853 ng/ml). The area under the ROC curve (AUC) value for vitamin k1 was 0.984 the odd ratio result was 18.66.Conclusion:Our results suggest that vitamin K1 may contribute to maintain bone mineral density. Vitamin K1 may have a role in diagnosing post-menopausal osteoporosis. Vitamin K1 may be a valuable diagnostic as well as therapeutic marker in post-menopausal osteoporosis.

Vitamin K is an essential fat-soluble vitamin. The role of vitamin K as a cofactor involved in blood coagulation is well demonstrated. In the past two decades, vitamin K has been receiving more attention due to its role in bone health and metabolism. Vitamin K plays a role in activation of vitamin K-dependent proteins, which are involved not only in blood coagulation but in bone metabolism and the inhibition of arterial calcification. Numerous studies have exhibited the importance of vitamin K in bone health. The bone mineral density (BMD) does not remain steady with age, particularly declining after menopause. Osteoporosis is a metabolic bone disease of reduced bone density, fragile bone, and elevated susceptibility to fracture. A greater understanding of the biological linkages between vitamin K and bone may conduce to new treatment for osteoporosis that may improve bone density and prevent the adverse outcomes of osteoporosis.