No effect of vitamin K1 intake on bone mineral density and fracture risk in perimenopausal women

Introduction: Vitamin K functions as a co-factor in the post-translational carboxylation of several bone proteins, including osteocalcin. Aim: The aim of this study was to investigate the relationship between vitamin K-1 intake and bone mineral density (BMD) and fracture risk in a perimenopausal Danish population. Design: The study was performed within the Danish Osteoporosis Prevention Study (DOPS), including a population-based cohort of 2,016 perimenopausal women. During the study approximately 50% of the women received hormone replacement therapy (HRT). Associations between vitamin K-1 intake and BMD were assessed at baseline and after 5-years of follow-up (cross-sectional design). Moreover, associations between vitamin K-1 intake and 5-year and 10-year changes in BMD were studied (follow-up design). Finally, fracture risk was assessed in relation to vitamin K-1 intake (nested case-control design). Results: In our cohort, dietary vitamin K-1 intake (60 mu g/day) was close to the daily intake recommended by the Food and Agriculture Organization (FAO). Cross-sectional and longitudinal analyses showed no associations between intake of vitamin K-1 and BMD of the femoral neck or lumbar spine. Neither did BMD differ between those 5% that had the highest vitamin K-1 intake and those 5% that had the lowest. During the 10-years of follow-up, 360 subjects sustained a fracture (cases). In a comparison between the cases and 1,440 controls, logistic regression analyses revealed no difference in vitamin K-1 intake between cases and controls. Conclusion: In a group of perimenopausal and early postmenopausal women, vitamin K-1 intake was not associated with effects on BMD or fracture risk.