Fig. 1: PRISMA flowchart of the trial selection process.
Excluded RCTs of supplementation in CRC patients were the D-health trial (ongoing trial,40) D2dca trial (not yet published); trials by Lappe et al.52 solely reported cancer incidence, but not survival outcomes; Baron et al.11 reported CRC incidence in an adenoma cohort, but with only 14 CRC cases.53 The excluded RCT of supplementation in population cohorts was the VIDA trial as CRC deaths were not reported or available on request;10 the RECORD trial reported CRC deaths,39 but a hazard ratio (HR) was not reported or available on request, so was excluded from meta-analysis. The Golubic et al.31 trial was not included in the meta-analysis of trials in CRC patients due to a high risk of bias, see below.
