Vitamin D deficiency and arterial wall stiffness in children with chronic kidney disease.

Arterial wall stiffness is a recognized complication in children with chronic kidney disease (CKD). Vascular abnormalities in these patients are shown to predate cardiac abnormalities such as left ventricular hypertrophy and diastolic dysfunction. The etiology of vascular abnormalities in these patients currently is not clear. This study explored the relationship between various parameters of calcium-phosphorus metabolism including 25-hydroxy vitamin D and arterial wall stiffness in pediatric patients with CKD. This study investigated a cohort of 43 children with CKD who had no history of underlying congenital or structural cardiac disease. The Augmentation Index (AI), a measure of peripheral arterial reflective properties using radial artery tonometry, was used as an indirect measure of central aortic stiffness. Serum biochemical markers of calcium-phosphorus metabolism were simultaneously measured. Univariate testing showed that AI correlated with worsening kidney function. Serum 25-hydroxy vitamin D levels were low and correlated negatively with AI (r = -0.39; p < 0.05). Multiple regression analysis showed that 25-hydroxy vitamin D was the only significant independent predictor of increased central arterial stiffness in the subgroup of children receiving hemodialysis. No association was observed between AI and any other measured biochemical parameter of calcium-phosphorus metabolism. This is the first study to investigate pediatric patients with CKD that suggests an association between nutritional vitamin D deficiency and increased arterial stiffness in children with CKD. The pathophysiologic mechanisms of vitamin D that regulate increased arterial stiffness need to be integrated further in pediatric CKD patients.