Routine Vitamin Supplementation to Prevent Cancer: Update of the Evidence from Randomized Controlled Trials 1999–2002

developed draft recommendations on the use of vitamin supplements to prevent cancer and cardiovascular disease, drawing on systematic reviews of the evidence available from randomized trials and well-conducted observational studies. The evidence pertaining to vitamin supplementation and cancer was originally summarized for the USPSTF in a manuscript covering publications through the end of 1999. To help the USPSTF finalize their draft recommendations, we updated the literature review through the end of 2002, focusing on the randomized trial evidence that was the basis of the draft recommendations. Methods An electronic search completed on December 23, 2002, identified relevant studies from the MEDLINE database of publications from 1999 through December 2002. The search was limited to publications in English and studies involving human subjects. The MEDLINE search terms included precancerous conditions, neoplasms, antioxidants, vitamins/administration and dosage, and vitamins/therapeutic use, as well as “randomized” or “controlled” or “clinical” trial. (See Evidence Table 1.)