Objectives: We performed this meta-analysis to estimate the association between vitamin B6 intake and colorectal cancer risk.
Methods: Prospective cohort studies on vitamin B6 intake and colorectal cancer risk were identified by searching databases from the period of 1960 to 2016. Results from individual studies were synthetically combined using Stata 13.0 software.
Results: A total of 10 prospective cohort studies including 13 data sets were included in our meta-analysis, containing 7,817 cases and 784,550 subjects. The combined relative risks (RR) of colorectal cancer for the highest vitamin B6 intake compared with the lowest vitamin B6 intake was 0.88 [95% confidence intervals (CIs): 0.77-1.02]. Dose-response meta-analysis based on five eligible studies showed that for each additional 3 and 5 mg of vitamin B6 intake, the risk would decrease by 11% (RR: 0.89, 95%CI: 0.81-0.98) and 17% (RR: 0.83, 95%CI: 0.71-0.97), respectively. Little evidence of publication bias was found.
Conclusion: This meta-analysis provides evidence of a nonsignificant decrease in colorectal cancer risk associated with the high level of vitamin B6 intake, but the risk in dose-response analysis is significant. However, the latter finding is based on a limited number of studies, which should be interpreted with caution.