Dietary inflammatory index and odds of colorectal cancer in a case-control study from Jordan

Dietary components that promote inflammation of the colon have been suggested to be risk factors in the development of colorectal cancer (CRC). The possible link between inflammatory potential of diet and CRC has been investigated in several developed or Western countries. Despite the fact that dietary choices in the Middle East differ markedly from those in the West, results have not been reported from any study conducted in a Middle-Eastern population. We examined the association between dietary inflammatory index (DII) scores and CRC in a case-control study conducted in Jordan. This study included 153 histopathologically confirmed CRC cases and 202 disease-free control subjects' frequency matched on age, sex, and occupation. Data were collected between January 2010 and December 2012, using interviewer-administered questionnaires. DII scores were computed from dietary data reported using a food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for age, sex, education, physical activity, body mass index, smoking, and family history of CRC. Subjects with higher DII scores were at increased odds of CRC, with the DII being used both as a continuous variable (OR_continuous = 1.45, 95% CI: 1.13-1.85; 1-unit increase corresponding to ≈20% of its range in the current study) and as a categorical variable (OR_{tertile 3 vs tertile 1} = 2.13, 95%CI: 1.23-3.72). Our results, based on a Jordanian population, add to the growing literature indicating that a pro-inflammatory diet is associated with increased odds of CRC.