Effects of folic acid supplementation on overall and site-specific cancer incidence during the randomised trials: meta-analyses of data on 50,000 individuals.

ABSTRACT:

Background

Some countries fortify flour with folic acid to prevent neural tube defects but others do not, partly because of concerns about possible cancer risks. We aimed to assess any effects on site-specific cancer rates in the randomised trials of folic acid supplementation, at doses higher than those from fortification.

Methods

In these meta-analyses, we sought all trials completed before 2011 that compared folic acid versus placebo, had scheduled treatment duration at least 1 year, included at least 500 participants, and recorded data on cancer incidence. We obtained individual participant datasets that included 49,621 participants in all 13 such trials (ten trials of folic acid for prevention of cardiovascular disease [n=46,969] and three trials in patients with colore

SUBMITTER: Vollset SE 

PROVIDER: S-EPMC3836669 | biostudies-literature | 2013 Mar

REPOSITORIES: biostudies-literature