Vitamin D insufficiency and deficiency in children with chronic kidney disease

BACKGROUND AND OBJECTIVES: Hypovitaminosis D is a frequent condition in normal populations. Children with chronic kidney disease (CKD) present a high risk of developing complications due to hypovitaminosis D. Our aim was to determine the frequency of vitamin D insufficiency/deficiency in children with different stages of CKD who were followed up at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia. DESIGN AND SETTING: University hospital-based case-control study of children followed up between March 2010 and March 2011. PATIENTS AND METHODS: Blood was extracted from children with CKD to measure urea, creatinine, hemoglobin, calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone (iPTH), and vitamin D3 levels. We calculated correlations between iPTH and vitamin D levels, and associations between vitamin D levels and CKD stages. RESULTS: The frequency of vitamin D insufficiency/deficiency was high among the cases and controls. Children with CKD had significantly lower levels of vitamin D than their peers with normal kidney function (P=.05) with a mean (SD) level of 17.5 (9.9) ng/mL versus 21.0 (13.4) ng/mL for the control group. Among the children with CKD, 36 (45.0%) had vitamin D insufficiency, 24 (30.0%) had vitamin D deficiency, and 10 (12.5%) had severe deficiency. There was a positive correlation between vitamin D3 level and CKD stages (Kendall tau=0.22, P=.003). A significant association existed between glomerular filtration rate and vitamin D3 deficiency (P=.002). There was a significant negative correlation between iPTH and vitamin D3 concentrations (Spearman correlation coefficient=-0.27, P=.01). A significant association existed between age and vitamin D3 level (P<.0001). CONCLUSION: Vitamin D insufficiency/deficiency is more frequent in children with CKD than in those with normal kidney function.