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

Several epidemiological studies have assessed the ability of vitamin B₂ to prevent colorectal cancer (CRC), but the results are controversial results. We conducted a dose-response meta-analysis to investigate the association between vitamin B₂ and CRC risk.

We 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.

A total of 14 studies reporting vitamin B₂ intake and two studies reporting blood vitamin B₂ concentration, comprising 14,934 cases and 1593 cases, respectively, were included in the meta-analysis. Vitamin B₂ intake was inversely associated with CRC risk (RR = 0.87; 95% CI 0.81-0.93). Similar results were found for total vitamin B₂ intake from diet and supplements (RR = 0.86; 95% CI 0.78-0.94) and dietary vitamin B₂ 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 B₂ intake increased to 5 mg/day. In addition, high blood concentrations of vitamin B₂ could also reduce the CRC risk (RR = 0.74; 95% CI 0.59-0.92).

This dose-response analysis indicates that vitamin B₂ intake is inversely associated with CRC risk. The inverse association may also exist between blood vitamin B₂ concentration and CRC risk. These results suggest the importance of vitamin B₂ intake in the prevention of CRC.