Adherence to the Mediterranean diet and colorectal cancer risk: a large case control study in the Moroccan population.

Abstract

Objective: The Mediterranean diet (MD) is a dietary pattern associated with several health benefits, including reduction of risk for various cancers. We conducted a study to investigate associations between adherence to the MD and colorectal cancer (CRC) subtype risk among Moroccan adults.

Design: A matched case-control study.

Setting: The five major university hospitals in Morocco.

Participants: A total of 3032 subjects (1516 CRC patients and 1516 controls) matched on age, sex and center, were recruited between September 2009 and February 2017 at five major hospitals in Morocco. Diet was assessed using a validated Food Frequency Questionnaire (FFQ). Adherence to the Mediterranean diet was assessed through a score, ranging from 0 (no adherence) to 10 (maximal adherence) and divided into three categories (low, middle and high). Conditional logistic regression was performed to calculate multivariable odd ratios (OR) and 95% confidence intervals (CI) with low adherence (score 0-3) as referent, adjusting for potential confounding factors.

Results: Close adherence to the Mediterranean diet (score 6-9) was associated with reduced risk of CRC (ORa = 0.74, 95% CI 0.63-0.86); rectal cancer (ORa = 0.73, 95% CI 0.58- 0.90) and colon cancer (ORa = 0.74, 95% CI 0.60-0.92).

Conclusion: Our study, conducted in a southern Mediterranean population, adds to the evidence suggesting a protective effect of MD against CRC risk.