INTRODUCTION
chronic kidney disease, CKD-MBD, bone loss, bone disorder, soft-tissue calcification
BONE LOSS, MINERALIZATION, BONE DISORDER
As kidney function declines, disturbances in the mineral metabolism cause abnormalities in bone turnover, mineralization and bone loss, as well as increased vascular and other soft-tissue calcification, the so-called chronic kidney disease–mineral and bone disorder (CKD-MBD) [BMD may be affected by vitamin K status. In observational studies, vitamin K levels were positively associated with BMD in the elderly general population [Patients treated with dialysis are very often vitamin K deficient, with highly elevated levels of vitamin K–dependent proteins. Vitamin K supplementation has been demonstrated to improve vitamin K status, as systemic levels of osteocalcin [OC; as undercarboxylated osteocalcin (ucOC)], matrix Gla protein [MGP; as dephosphorylated-uncarboxylated matrix Gla protein (dp-ucMGP)] and protein induced by vitamin K absence II (PIVKA-II) significantly decreased during supplementation [The aim of this randomised, double-blind, placebo-controlled, study was to investigate the effect of vitamin K supplementation on BMD in patients on dialysis treatment.