Vitamin D Deficiency in Children With Chronic Kidney Disease: Uncovering an Epidemic

BACKGROUND. Vitamin D deficiency in children adversely affects bone development by reducing mineralization. Children with chronic kidney disease are at risk for altered bone development from renal osteodystrophy and concomitant vitamin D deficiency. The pediatric Kidney Disease Outcomes Quality Initiative guidelines suggest measuring serum 25-hydroxyvitamin D (25[OH] D) levels if serum parathyroid hormone levels are above the target range for chronic kidney disease stages 2 and beyond, but the magnitude of vitamin D deficiency in children with chronic kidney disease is not well studied. OBJECTIVES. The purpose of this work was to determine whether children with chronic kidney disease had vitamin D deficiency, to evaluate whether the prevalence of vitamin D deficiency changed over time, and to examine seasonal and ethnic differences in 25(OH) D levels. METHODS. 25(OH) D levels in children with chronic kidney disease (stages 1-5) were measured over a 10-year period from 1987 to 1996. Data were also collected for a contemporary group of patients from 2005 to 2006. RESULTS. The prevalence of vitamin D deficiency ranged from 20% to 75% in the decade studied. There was a significant trend for decreasing 25(OH) D levels over the decade, both at the group and individual levels. Seasonal variation was noted. In our contemporary population with chronic kidney disease, the mean 25(OH) D level was 21.8 ng/mL; we found a prevalence of vitamin D deficiency of 39%. Black and Hispanic patients had lower levels of 25(OH) D than white patients. CONCLUSIONS. Children with chronic kidney disease have great risk for vitamin D deficiency, and its prevalence was increasing yearly in the studied decade. Contemporary data show that vitamin D deficiency remains a problem in these children. Sunlight exposure and ethnicity play a role in levels of 25(OH) D. Our data support the recent pediatric Kidney Disease Outcomes Quality Initiative guidelines for measurement of 25(OH) D levels in children with chronic kidney disease and secondary hyperparathyroidism. Pediatrics 2009; 123: 791-796