Browsing by Subject "luun mineraalitiheys"

Introduction: Vitamin K is required in the carboxylation reaction of osteocalcin (OC). Concentration of serum undercarboxylated osteocalcin (ucOC) is regarded as a sensitive marker of vitamin K status. Low serum concentration of ucOC has been inversely associated with bone mineral density (BMD). However, the role of dietary vitamin K in bone health remains unclear. The aim of the study was to investigate the associations among vitamin K intake, serum OC concentrations and tibial BMD, bone mineral content (BMC) and bone strength indices (BSI, CSI, SSI) in Finnish middle-aged women. Methods: A sample of 364 37- to 47-year-old premenopausal females who participated in the PHOMI Study was included in the analyses. Fasting blood samples were collected, as well as habitual dietary intake by 3-day food records and food frequency questionnaires. Serum total osteocalcin (totOC), carboxylated osteocalcin (cOC) and ucOC were assessed by two-site immunoassay. Bone traits from distal and proximal sites of tibia were measured with peripheral quantitative computed tomography (pQCT). The data was analysed by analysis of variance and covariance as well as correlation analysis and partial correlation analysis adjusted for height, weight, physical activity, dietary calcium intake, smoking and serum 25-hydroxy vitamin D concentrations. Results: Dietary vitamin K was not associated with bone traits nor serum OC concentrations (p>0.05). Serum ucOC correlated negatively with BMC (r=-0.133, p=0.014), BMD (r=-0.164, p=0.002) and BSI (r=-0.147, p=0.006) in distal tibia and with BMD (r=-0.130, P=0.015) in proximal tibia. Serum cOC correlated negatively with BMD in distal tibia (r=-0,124, p=0,021) and in proximal tibia (r=-0,132, p=0,014). Serum totOC correlated negatively with BMC (r=-0,148, p=0,004) in distal tibia and with BMD (r=-0,175, p=0,001) and BSI (r=-0,171, p=0,002) in proximal tibia. Conclusion: There were no associations between vitamin K intake and bone health in the adjusted model in the current study but serum OC concentrations correlated negatively with some bone traits. Differences in bioavailability of vitamin K and high intake of calcium and vitamin D in the study sample could explain why associations were not found between dietary vitamin K and bone traits. Moreover, the association between vitamin K and bone traits may be different in pre- and postmenopausal women.