BACKGROUND

Results regarding the association of dietary fiber intake with colorectal tumor risk remain inconsistent. The association may differ between smokers and nonsmokers. We evaluated this hypothesis in a large colonoscopy-based case-control study.

METHODS

Dietary fiber intakes were estimated by a food frequency questionnaire designed to capture dietary intakes in the study population. Unconditional logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence limits (95% CLs) with adjustment for potential confounders. Analysis also was stratified by cigarette-smoking status and sex.

RESULTS

Overall, colorectal polyps (P-trend < 0.001), including adenoma only (P-trend = 0.006), were associated inversely with high dietary fiber intake. When stratified by smoking status, this inverse association was only observed among tobacco smokers, but not among never smokers, (Pheterogeneity = 0.039) for either males or females and for all participants. The protective effect was observed only among smokers for high-risk adenomas (Pheterogeneity = 0.018) and low-risk adenomas, but not for never smokers. The protective effect was particularly strong for high-risk adenomas in smokers. Consuming more than 19.9 g/day of dietary fiber was associated with a 41-44% decreased risk for high-risk adenomas among smokers (P-trend < 0.001).

CONCLUSIONS

Cigarette smoking may modify the association of dietary fiber intake and the risk of colorectal polyps, especially high-risk adenoma risk.

Citation Format: Zhenming Fu, Martha J. Shrubsole, Wei Zheng. Dietary fiber intake reduces colorectal polyp risk in cigarette smokers. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4817. doi:10.1158/1538-7445.AM2013-4817