Vitamin B2 intake reduces the risk for colorectal cancer: a dose-response analysis

PurposeSeveral epidemiological studies have assessed the ability of vitamin B-2 to prevent colorectal cancer (CRC), but the results are controversial results. We conducted a dose-response meta-analysis to investigate the association between vitamin B-2 and CRC risk.MethodsWe searched the PubMed and EMBASE database until January 3, 2018 to identify relevant studies. The pooled relative risks (RRs) with the corresponding 95% confidence intervals (CIs) were calculated using a random-effects model or fixed-effects model. The dose-response relationship was assessed by restricted cubic splines.ResultsA total of 14 studies reporting vitamin B-2 intake and two studies reporting blood vitamin B-2 concentration, comprising 14,934 cases and 1593 cases, respectively, were included in the meta-analysis. Vitamin B-2 intake was inversely associated with CRC risk (RR=0.87; 95% CI 0.81-0.93). Similar results were found for total vitamin B-2 intake from diet and supplements (RR=0.86; 95% CI 0.78-0.94) and dietary vitamin B-2 intake (RR=0.89, 95% CI 0.82-0.98) in subgroup analyses. The dose-response model indicated a non-linear trend, and CRC risk was reduced by 10% when vitamin B-2 intake increased to 5mg/day. In addition, high blood concentrations of vitamin B-2 could also reduce the CRC risk (RR=0.74; 95% CI 0.59-0.92).ConclusionsThis dose-response analysis indicates that vitamin B-2 intake is inversely associated with CRC risk. The inverse association may also exist between blood vitamin B-2 concentration and CRC risk. These results suggest the importance of vitamin B-2 intake in the prevention of CRC.