Dietary diversity score (DDS) and odds of colorectal cancer and adenoma: a case-control study.

Despite mounting evidence that dietary factors might have a protective role against risk of cancer, few studies have assessed the relationship between diet diversity with colorectal cancer (CRC) and colorectal adenoma (CRA). Thus, we examined the relationship between dietary diversity score (DDS) and the odds of CRC and CRA. Overall, 129 CRC diagnosed patients, 130 CRA diagnosed cases and 240 healthy hospitalised controls were studied. DDS was calculated based on information on the usual diet that was assessed by a valid and reliable food frequency questionnaire (FFQ). Multivariate logistic regression was used to estimate the relationship between DDS and odds of colorectal cancer and adenoma. After adjusting for potential confounders, the diversity of grains is associated with the increased odds of CRC (ORgrains: 2·96 (1·05-8·32); P = 0·032), while the diversity of vegetables and fruits are associated with decreased odds of CRC (ORvegetables: 0·31 (0·16-0·62); P = 0·001, ORfruits: 0·37 (0·23-0·61); P < 0·001). The diversity of vegetables, fruits and dairy are inversely associated with odds of CRA (ORvegetables: 0·41 (0·21-0·78); P = 0·007, ORfruits: 0·58 (0·36-0·93); P = 0·021, ORdairies: 0·56 (0·37-0·83); P = 0·004). Also, higher DDS was related to decreased odds of both CRC (OR: 0·41 (0·23-0·72); P for trend = 0·002) and CRA (OR: 0·36 (0·21-0·65); P for trend = 0·001). Our results indicated that higher dietary diversity and particularly a diet varied in fruits and vegetables may reduce the odds of CRC and CRA. Also, the consumption of dairy products may decrease the odds of CRC, whereas the consumption of grains may increase the odds of CRC.

Dietary Inflammatory Index and Odds of Colorectal Cancer and Colorectal Adenomatous Polyps in A Case-Control Study from Iran.

BACKGROUND: Chronic inflammation is implicated in the development of colorectal cancer (CRC) and its precursor; colorectal adenomatous polyps (CAP). Some dietary factors are important triggers for systemic inflammation. Therefore, the present study aimed to investigate the association between the dietary inflammatory index (DII®) and the risk of CRC and CAP in an Iranian case-control study. METHODS: 134 newly diagnosed CRC patients, 130 newly diagnosed CAP patients, and 240 hospitalized controls were recruited using convenience sampling. Energy-adjusted DII (E-DII) scores were computed based on dietary intake assessed using a reproducible and valid 148-item food frequency questionnaire. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI) after adjusting for confounders. RESULTS: The E-DII score ranged between -4.23 (the most anti-inflammatory score) to +3.89 (the most pro-inflammatory score). The multivariable-adjusted ORs for participants in the 3rd tertile compared to the 1st tertile was 5.08 (95%CI: 2.70-9.56; P-trend < 0.0001) for CRC and 2.33 (95% CI: 1.30-4.02; P-trend = 0.005) for CAP. CONCLUSIONS: Our findings suggest that more pro-inflammatory diets, indicated by higher E-DII scores, might increase the risk of both CRC and CAP. Future steps should include testing these associations in a prospective setting in Iran.