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 .
Age-Related Changes in Serum Undercarboxylated Osteocalcin and its Relationships with Bone Density, Bone Quality, and Hip Fracture
Abstract . The effect of the degree of carboxylation of osteocalcin ( OC ) on the properties of bone is unclear . The aim of this study was to relate serum concentrations of total OC ( tOC ) and undercarboxylated OC ( ucOC )  , measured with a two-site immunoassay , to bone mineral density ( BMD ) at the femoral neck and ultrasonic transmitted velocity ( UTV ) at the os calcis in 257 women aged 60–99 years , 22 of whom had sustained a hip fracture . There was an increase in tOC ( r = 0.19 , P= 0.003 ) and ucOC ( r = 0.20 , P= 0.002 ) with age . No significant difference in tOC or ucOC between subjects with and without hip fracture was found . Serum tOC was negatively correlated with femoral neck BMD ( r = −0.23 , P= 0.0001 ) and os calcis UTV ( r = −0.29 , P= 0.0001 ) and partial correlations indicated that these relationships were independent of age . Serum ucOC also correlated negatively with os calcis UTV ( r = −0.21 , P= 0.001 ) and less strongly with femoral neck BMD ( r = −0.13 , P= 0.052 ) . After adjusting for age , only the relationship between ucOC and os calcis UTV remained significant ( r = −0.16 , P= 0.017 ) . It is concluded that in women over 60 years , the increase in tOC reflects an age-related rise in bone remodeling , whereas the increase in ucOC reflects an age-related fall in vitamin K status . The stronger relationship of ucOC with UTV than BMD suggests that the rise in ucOC may perhaps relate more to changes in bone quality than mineral content . Higher serum ucOC concentrations in subjects with a history of hip fracture could not be confirmed
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 .