Vitamin D Repletion in Chronic Kidney Disease

The reason for doing this research is that people with kidney disease often suffer from heart disease. Why this happens is not fully known. A possible cause may be high blood levels of a substance made by bacteria called "endotoxin". The blood levels of this substance are high in people with medium-level kidney disease. We want to know if replacing normal amounts of Vitamin D can help lower the levels of this substance. We also want to know if replacing normal amounts of Vitamin D is associated with other changes that may help heart disease. We hope that our research will help figure out if levels of this substance can be lowered by replacing normal amounts of Vitamin D. Normal subjects are enrolled to have a 'control' set for comparison purposes.