NCT00153816 2017-03-15Vitamin D/Calcium Polyp Prevention StudyDartmouth-Hitchcock Medical CenterPhase 2/3 Completed2,813 enrolled 15 charts
NCT00870961 2013-09-16Vitamin D Supplement in Preventing Colon Cancer in African Americans With Colon PolypsNorthwestern UniversityPhase NA Terminated22 enrolled