Chronic kidney disease and vitamin D: how much is adequate?

Mehrotra et al. demonstrate that there still is hypovitaminosis D in adults with chronic kidney disease (CKD) in the United States, and this defect is associated with increased risk for death. Definition of the adequate amount of vitamin D, however, is still uncertain; polymorphisms of the gene encoding the vitamin D receptor might be responsible for this uncertainty. People carrying less efficient variants of the receptor might need higher amounts of vitamin D.