Adherence to 2018 WCRF/AICR recommendations and colorectal cancer risk: A case-control and Mendelian randomization study.

[BACKGROUND] The association between adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) recommendations and colorectal cancer (CRC) risk remains inconsistent in epidemiological studies, with particularly sparse data from Chinese populations. This study aimed to evaluate this relationship comprehensively.

[METHODS] We conducted a case-control study involving 3030 incident CRC cases and 3044 age- and sex-matched controls. Multivariable logistic regression models were used to examine the association between adherence to the seven-point 2018 WCRF/AICR score, the 2018 WCRF/AICR dietary score, and individual recommendations with CRC risk, with results presented as odds ratios (ORs) and 95% confidence intervals (95% CIs). Additionally, a two-sample Mendelian randomization (MR) study was performed to assess the causal relationship between individual recommendations and CRC risk.

[RESULTS] Both a higher 2018 WCRF/AICR score (adjusted OR: 0.52; 95% CI: 0.43, 0.64; P < 0.001) and a higher 2018 WCRF/AICR dietary score (adjusted OR: 0.51; 95% CI: 0.42, 0.63; P < 0.001) were associated with a reduced CRC risk in Chinese populations. Adherence to individual recommendations on physical activity, plant-based food intake, red/processed meat intake limitation and alcohol intake limitation showed an inverse association with CRC risk. Of these, plant-based food intake and alcohol consumption limitation were further supported by MR analyses.

[CONCLUSIONS] Greater adherence to the 2018 WCRF/AICR recommendations, particularly those related to plant-based food intake and alcohol intake limitation, was inversely associated with the risk of CRC.