Published online Jul 28, 2020. doi: 10.3748/wjg.v26.i28.4108
Peer-review started: February 28, 2020
First decision: March 21, 2020
Revised: April 3, 2020
Accepted: July 16, 2020
Article in press: July 16, 2020
Published online: July 28, 2020
Epidemiological evidence suggests that some foods may both protect against and promote the development of colorectal cancer (CRC). However, foods are not consumed in isolation but as part of a dietary pattern; therefore, the actual effect of diet on disease risk may be observed only when all components are considered jointly. For this purpose, several diet quality indexes have been developed using point systems to measure whole diet quality based on the alignment of food choices with dietary recommendations.
Some diet quality indexes have been used to begin assessing the relationships between overall diet quality and CRC risk, and the results show that high scores in these indices are associated with a lower CRC risk. However, the results vary considerably according to the index used and other factors such as sex and age. Therefore, there is a need to further examine these relationships in diverse population studies.
To study the relationships between food groups, diet quality and CRC risk, in an adult population of the Basque Country (North of Spain).
This observational study included 308 patients diagnosed with CRC and 308 age- and sex-matched subjects as controls. During recruitment, dietary, anthropometric, lifestyle, socioeconomic, demographic and health status information was collected. Dietary intake was assessed using a short food frequency questionnaire that was adapted and validated for this population. Adherence to the dietary recommendations was evaluated utilizing the Healthy Eating Index for the Spanish Diet and the MedDietScore. Statistical analyses were performed using IBM SPSS Statistics for Windows, version 22.0 (IBM Corp., Armonk, NY, United States) and STATA 13.0 (StataCorp LP, TX, United States). Conditional logistic regressions were used to evaluate the associations of food group intakes, diet quality scores, categorized in tertiles, with CRC risk.
The adjusted models for potential confounding factors showed a direct association between milk/dairy products consumption, in particular high-fat cheeses [odds ratio (OR) third tertile vs first tertile = 1.87, 95% confidence intervals (CI): 1.11-3.16], and CRC risk. While the consumption of fiber-containing foods, especially whole grains (OR third tertile vs first tertile = 0.62, 95%CI: 0.39-0.98), and fatty fish (OR = 0.53, 95%CI: 0.27-0.99) was associated with a lower risk for CRC. Moreover, higher MD adherence was associated with a reduced CRC risk in adjusted models (OR = 0.40, 95%CI: 0.20-0.80).
Direct associations were found for high-fat cheese, whereas an inverse relation was reported for fiber-containing foods and fatty fish, as well as adherence to a Mediterranean dietary pattern.
Future studies are needed to better understand the influence of the dietary habits on CRC prevention in this population that can provide leads for the design and tailoring of future interventions, and guide counselling strategies for promoting a healthy lifestyle.