Dietary Inflammatory Index and Odds of Colorectal Cancer in a Case- Control Study from Iran

Abstract

Background: In Iran, colorectal cancer (CRC) is the third and fourth leading cause of cancer incidence among men<br />and women, respectively. Diet and inflammation have been suggested as important risk factors for CRC. We examined<br />the association between dietary inflammatory index (DII) scores and CRC in a case-control study conducted in Iran.<br />Methods: This study included 71 CRC cases and 142 controls hospitalized for acute non-neoplastic diseases. DII<br />scores were computed from dietary intake assessed by a previously validated food frequency questionnaire. Logistic<br />regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI) adjusted for age, sex,<br />education, energy intake, exercise, body mass index (BMI), smoking, family history of cancer, and history of aspirin,<br />acetaminophen, and multivitamin use. Results: Subjects with higher DII scores (i.e., indicating a more pro-inflammatory<br />diet) had a higher odds of CRC with the DII being used as both a continuous variable (OR continuous = 2.20, 95% CI:<br />1.22-3.87) and as a categorical variable (OR tertile 3 vs tertile1 = 2.47, 95%CI: 1.10-5.55). Conclusion: These results<br />indicate that a pro-inflammatory diet is associated with increased odds of CRC in this Iranian population.