Adherence to the World Cancer Research Fund/American Institute for Cancer Research 2018 Recommendations for Cancer...

The World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) 2018 diet, nutrition, and physical activity recommendations aim to reduce cancer risk. We examined adherence to the WCRF/AICR recommendations and colorectal cancer risk in two prospective cohorts.

We followed 68,977 women in the Nurses' Health Study and 45,442 men in the Health Professionals Follow-up Study from 1986 until 2012. We created cumulatively averaged WCRF/AICR scores using updated diet, adiposity, and physical activity data from questionnaires, and used Cox regression to estimate sex-specific HRs and 95% confidence intervals (CI) for incident colorectal cancer.

We documented 2,449 colorectal cancer cases. Men in the highest quintile of the WCRF/AICR lifestyle score had a lower risk of colorectal cancer compared with those in the lowest quintile (HR_Q5vsQ1 = 0.64; 95% CI, 0.52-0.77). The result was weaker in women (HR_Q5vsQ1 = 0.86; 95% CI, 0.72-1.02; P _{heterogeneity by sex} = 0.006). When analyzing the diet recommendations alone, we similarly observed stronger inverse associations in men (HR_Q5vsQ1 = 0.74; 95% CI, 0.61-0.90) compared with women (HR_Q5vsQ1 = 0.93; 95% CI, 0.77-1.12; P _{heterogeneity by sex} = 0.06). In men, the lifestyle score was more strongly inversely associated with risk of distal colon cancer compared with proximal colon or rectal cancer (P _{common effects} = 0.03); we did not observe significant differences between anatomic locations in women.

The 2018 WCRF/AICR cancer prevention recommendations are associated with lower colorectal cancer risk in men, with weaker results in women.

Consideration of adiposity and physical activity in conjunction with diet is important for colorectal cancer prevention.