The impact of adherence to cancer prevention recommendations on cancer incidence and mortality in a cohort of Canadian adults

BACKGROUND: Adherence to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations has been associated with reduced cancer risk; however, Canadian evidence remains limited. We examined associations between adherence to these recommendations and cancer incidence and mortality in a Canadian cohort. METHODS: We conducted a prospective cohort analysis of 16,053 participants in the British Columbia Generations Project with no cancer diagnosis at recruitment. Participants were followed from 2009 to 2022 through linkage with the British Columbia Cancer Registry. Adherence to five behavioural factors (body weight, physical activity, fruit and vegetable intake, alcohol consumption, and smoking) was scored (1 = full, 0.5 = partial, 0 = non-adherence) to generate a composite adherence score (range 0-5). Multivariable Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for cancer incidence and mortality. RESULTS: During follow-up, 2,171 incident cancers and 516 cancer deaths were identified. Compared with non-adherence, full adherence was associated with lower overall cancer incidence (HR = 0.68, 95% CI: 0.54-0.78) and cancer mortality (HR = 0.66, 95% CI: 0.49-0.88). In sex-specific analyses, full adherence was associated with lower cancer incidence and mortality among both females and males. Full adherence was also associated with reduced breast, colorectal, and lung cancer risk. Findings were robust in sensitivity analyses excluding cancers diagnosed within the first two years of follow-up. CONCLUSIONS: Greater adherence to cancer prevention recommendations was associated with lower cancer incidence and mortality. IMPACT: These findings support integrated, multi-behaviour cancer prevention strategies in Canadian populations.