A new study has found that Vitamin D levels in children with chronic kidney disease are influenced more strongly by seasonal factors, the type of disease and nutritional supplementation than by common variants in vitamin D regulating genes. The findings, published in the Clinical Journal of the American Society of Nephrology (CJASN) identify certain modifiable and non-modifiable factors associated with vitamin D deficiency in children with CKD.

A team led by Anke Doyon, MD and Franz Schaefer, MD from the University of Heidelberg, Germany, looked at how various factors relate to vitamin D levels in 500 children with CKD who were residing in 12 European countries.

Among the major findings:

  • Two-thirds of the patients were classified as vitamin D deficient.
  • Patients who took vitamin D supplements had vitamin D levels that were 2 times higher than those who did not take supplements, and they had a lower prevalence of vitamin D deficiency.
  • Vitamin D levels were lower for certain kidney abnormalities, such as glomerulopathies
  • Vitamin D levels were lower in winter months than at other times of the year.
  • Certain genetic variants were also associated with vitamin D levels, but to a lesser extent than disease-associated factors and vitamin D supplementation.

“Vitamin D levels are influenced more strongly by seasonal factors, the type of disease and nutritional supplementation than by common variants in vitamin D regulating genes,” said. Doyon. “Supplementation practices should be reconsidered and intervention studies are needed to define guidelines how to monitor and treat vitamin D deficiency in children with chronic kidney disease.”