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

Document Type: Research Articles

Authors

1 Cancer Prevention and Control Program, University of South Carolina, Columbia, SC 29208, USA.

2 Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC 29208, USA.

3 Connecting Health Innovations LLC, Columbia, SC 29201, USA.

4 Department of Nutrition and Dietetics, Faculty of Medicine and Health Sciences, University Putra Malaysia, Selangor, Malaysia.

5 Department of Community Nutrition, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Abstract

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

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