The association of lifestyle and dietary factors with the risk for serrated polyps of the colorectum

Some serrated polyps of the colorectum are likely pre-invasive lesions, evolving through a newly recognized serrated pathway to colorectal cancer. To assess possible riskand protective factors for serrated polyps and particularly to explore differences in riskfactors between polyps in the right and left colorectum, we pooled data from three large multicenter chemoprevention trials. A serrated polyp was defined broadly as any serrated lesion (hyperplastic, sessile serrated adenoma, "traditional" serrated adenoma, mixed adenoma) diagnosed during each trial's main treatment period of ∼3 to 4 years. Using generalized linear regression, we computed riskratios and 95% confidence intervals as measures of the association between risk for serrated polyps and demographic, lifestyle, and dietary variables. Of the 2,830 subjects that completed at least one follow-up exam after randomization, 675 (23.9%) had at least one left-sided serrated polyp and 261 (9.2%) had at least one right-sided lesion. In the left colorectum, obesity, cigarette smoking, dietary fat, total energy intake, and red meat intake were associated with an increased riskfor serrated polyps. In the right colon, aspirin treatment was associated with a reduced riskand family history of polyps and folate treatment were associated with an increased riskf or serrated polyps. Our results suggest that several common lifestyle and dietary variables are associated with riskfor serrated polyps, and some of these may differ for the right and left colorectum. Copyright © 2009 American Association for Cancer Research.