How do you approach vitamin D supplementation in patients with chronic kidney disease, given the findings that vitamin D2 supplementation may lead to decreased conversion of 25-hydroxyvitamin D3 to 1,25-dihydroxyvitamin D3?  

In early 2000, there was a publication suggesting that ingesting vitamin D2 increases the destruction of vitamin D3 and therefore could increase the risk for vitamin D deficiency. Although I had never seen this happen in my clinic, we decided to conduct a study to evaluate what the effect of vitamin...