In addition, in the stratified analysis of other risk factors, the interaction between flavonols and CYP1A1 rs4646903 in relation to colorectal cancer risk was stronger among individuals older than 50 years (P for interaction = 0.03) and individuals who did not exercise regularly (P for interaction = 0.03), smoked (P for interaction = 0.006), or drank alcoholic beverages (P for interaction = 0.02) (Supplementary Table S3). This evidence concerns the gene CYP1A1 and colorectal cancer.