Assessment of vitamin K2 status in children with chronic kidney diseases

Abstract Background : Vitamin K2 plays a crucial role in the formation of osteocalcin in bones, matrix GLa protein in cartilage, and the walls of blood vessels. we aimed to investigate vitamin K2 status in children with CKD G5D, without KRT and after renal transplantation, and its relation to bone turnover by measuring bone turnover marker (bone alkaline phosphatase- BAP). Methods: We enrolled 75 patients classified into 3 groups: group A; CKD without KRT, group B; CKD G5D and group C; renal transplant recipients. Another 25 healthy individuals were involved as a control group. Under carboxylated osteocalcin (uOC) (as a sensitive indicator of vitamin K level) and BAP were measured in fasting blood samples in all patients. 24-hour dietary recall was used to assess vitamin k, calcium, and phosphorus intake. Vitamin and mineral intake was calculated as a percent of target requirements of age and sex-matched healthy children. Results: uOC was found significantly higher in the patient groups in comparison to the control group (p <0.001). The highest level of uOC was detected in the HD group. In all groups except the HD group, robust negative correlations were observed between uOC and both eGFR and vitamin K (%) levels. There was a statistically significant difference in uOC (p < 0.001) between those with history of bone fractures (No.= 7) compared to those without fractures (No.= 93). By logistic regression analysis, increasing uOC was associated with an increased likelihood of exhibiting bone fractures (p = 0.012). Conclusion: elevated uOC levels were observed in children with CKD and demonstrated a correlation with eGFR. Additionally, they exhibited a notable association with heightened bone turnover status, as indicated by BAP levels.