Summary Vitamin K may affect  bone mineral density and fracture incidence .
Since publication of a previous systematic review the integrity of some of the previous evidence has been question ed and further trials have been published .
Introduction This systematic review was design ed to assess the effectiveness of oral vitamin K supplementation for increasing bone mineral density  and reducing fractures in adults .
Undercarboxylated osteocalcin measured with a specific immunoassay predicts hip fracture in elderly women: the EPIDOS Study.
Increased levels of circulating undercarboxylated osteocalcin ( ucOC ) , measured indirectly with the hydroxyapatite ( HAP ) binding assay , have been shown to predict hip fracture risk in a small group of elderly institutionalized women . The aim of this study was to confirm these findings in a prospect i ve cohort study ( EPIDOS prospect i ve study ) of 7598 healthy , independently living women over 75 yr of age . One hundred and four women who sustained a hip fracture during a 22-month follow-up period were age matched with 255 controls who did not fracture . Baseline sample s were collected before hip fracture for measurement of total OC and ucOC , assessed either with the HAP binding assay or directly with a new enzyme-linked immunosorbent assay ( ELISA ) . This direct ELISA uses human recombinant noncarboxylated OC as a st and ard and two monoclonal antibodies , one of which was raised against the 14 - 30 Glu synthetic peptide . We found that the intra- and interassay variations are less than 11 % , and this assay exhibits a 5 % cross-reactivity with purified human bone OC , used as a source of carboxylated OC . ucOC levels measured with this ELISA correlated well with the HAP binding assay in the population of 359 elderly women ( r = 0.82 ; P < 0.0001 ) . We estimated the risk of hip fracture for women with levels of ucOC in the highest quartile of values for the 255 controls . We found that increased levels of ucOC measured by ELISA were associated with increased hip fracture risk with an odds ratio ( OR ) of 1.9 ( 95 % confidence interval , 1.2 - 3.0 ) , and the ELISA had a greater sensitivity than the HAP assay . In contrast , total OC was not associated with hip fracture risk . After adjustment for femoral neck bone mineral density ( BMD ) and mobility status assessed by gait speed , ucOC still predicted hip fracture with an OR of 1.8 ( 1.0 - 3.0 ) . Women with both femoral neck BMD in the lowest quartile and ucOC in the highest quartile were at higher risk of hip fracture , with an OR of 5.5 ( 2.7 - 11.2 ) , than those with only low BMD or high ucOC levels . In conclusion , we have developed a new specific ELISA for serum ucOC , with low cross-reactivity with carboxylated OC and increased specificity and sensitivity over the HAP assay . Using this new ELISA , we found that ucOC , but not total OC , predicts hip fracture risk independently of femoral neck BMD in elderly women drawn from the general population . Thus , ucOC measurement could be combined with bone mass determination to improve the assessment of hip fracture risk in elderly women
Summary Vitamin K may affect  bone mineral density and fracture incidence .
Since publication of a previous systematic review the integrity of some of the previous evidence has been question ed and further trials have been published .
Introduction This systematic review was design ed to assess the effectiveness of oral vitamin K supplementation for increasing bone mineral density  and reducing fractures in adults .