• 1College of Public Health,Department of Epidemiology and Biostatistics,University of Georgia,101 Buck Road,Health Sciences Campus,B.S. Miller Hall,Athens,GA 30602,USA.
• 2Cancer Prevention and Control Program and Department of Epidemiology & Biostatistics,Arnold School of Public Health,University of South Carolina,Columbia,SC,USA.

OBJECTIVE: The Dietary Inflammatory Index (DII)TM, which was developed to characterize the inflammatory potential of a person's diet, has been shown to be associated with inflammatory conditions such as cancer. The present study aimed to investigate the association between DII scores and colorectal adenoma (CRA), a pre-cancerous condition.

DESIGN: Responses to baseline dietary questionnaires were used calculate DII scores. In a cross-sectional study design, the association between DII scores and CRA prevalence was determined in men and women separately using logistic regression models.

SETTING: Ten cancer screening centres across the USA.

SUBJECTS: Participants were those included in the screening arm of the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial.

RESULTS: Among the 44 278 individuals included in these analyses, men with diets in the most inflammatory quartile of DII scores had higher odds of all types of CRA (advanced, non-advanced and multiple (>1)) compared with those with diets in the least inflammatory quartile of DII scores. In fully adjusted models, compared with those with DII scores in quartile 1 (least inflammatory), males with DII scores in quartile 3 (adjusted odds ratio (aOR)=1·28; 95 % CI 1·12, 1·47) and quartile 4 (aOR=1·41; 95 % CI 1·23, 1·62) were more likely to have prevalent distal CRA. Higher DII scores, representing a more inflammatory diet, also were weakly associated with a higher prevalence of CRA in women.

CONCLUSIONS: Implementing an anti-inflammatory diet may be an effective means of primary prevention of CRA, especially in men.