Dietary pattern and lifestyle risk factors for sessile serrated precursors to colorectal cancer

Sessile serrated lesions (SSL) are recognised precursors to colorectal cancer. Little is known about risk factors for SSL due to their relatively recent clinical recognition as a cancer precursor and routine documentation of cases. Lifestyle and diet-related information were collected using validated questionnaires in a colonoscopy-based case-control study in Australia (257 SSL cases, 239 conventional adenoma (CA) cases, 180 polyp-free controls). <i>A posteriori</i> dietary patterns were derived from self-reported dietary intake in the past 12 months using principal component analysis. Multivariable-adjusted OR and 95 % CI were used to examine associations between lifestyle factors and dietary patterns on risk of SSL and CA <i>v</i>. polyp-free controls and SSL <i>v</i>. CA using logistic regression modelling. Use of anti-inflammatory medications was associated with reduced SSL risk (OR = 0·61; 95 % CI 0·38, 1·00), while current smoking was associated with increased SSL risk (OR = 1·96; 95 % CI 1·09, 3·53). Unlike CA, SSL risk was not increased by hormone replacement therapy use and current alcohol consumption but was increased by taller height. Higher adherence to a dietary pattern featuring processed meats, ready-made convenience foods and high-energy drinks was associated with increased SSL risk (OR = 2·13; 95 % CI 1·13, 4·00; <i>P</i>_trend = 0·03) and CA (OR = 2·60; 95 % CI 1·32, 5·09; <i>P</i>_trend = 0·005). Compared with CA, a dietary pattern featuring wholegrains, low-fat dairy products, nuts, seeds and oily fish was associated with reduced SSL risk (OR = 0·60; 95 % CI 0·36, 0·98; <i>P</i>_trend = 0·04). This study supports a healthy diet as primary prevention for both SSL and CA and reinforces smoking as a risk factor for SSL.