Adherence to the WHO's Healthy Diet Indicator and Overall Cancer Risk in the EPIC-NL Cohort

Background: A healthy dietary pattern defined by international recommendations of the World Health Organisation (WHO) has been shown to reduce overall mortality risk. It is unknown whether this healthy dietary pattern is associated with overall cancer incidence. Design: In total 35,355 men and women within the Dutch European Prospective Investigation into Cancer and Nutrition-cohort were followed for cancer occurrence. Diet was assessed through a validated food-frequency questionnaire. We computed a dietary score for all participants based on the seven WHO dietary guidelines for the prevention of chronic diseases (Healthy Diet Indicator (HDI)). We used the existing HDI score based on the 1990 WHO guidelines, and adapted it to meet with the 2002 WHO guidelines. Multivariate-adjusted Cox proportional hazards analysis was used to examine the association between adherence to the HDI and subsequent overall cancer risk. Results: A number of 3,007 new cancers were identified during a mean follow-up of 12.7 years. Adherence to the HDI was not associated with a reduced overall cancer risk. The hazard ratio (HR) of overall cancer associated with a one-point increment of the HDI was 0.96 (95% CI 0.89-1.03) in men, and 1.00 (95% CI 0.96-1.04) in women. Adherence to the HDI was not associated with smoking-related cancer ((HR men: 0.94 (95% CI 0.84-1.04); HR women: 1.00 (95% CI 0.94-1.07)), or alcohol-related cancer ((HR men: 1.02 (95% CI 0.87-1.20); HR women: 1.03 (95% CI 0.98-1.08)). Conclusions: Greater adherence to the WHO's Healthy Diet Indicator, a dietary pattern for prevention of chronic diseases, was not associated with reduced overall, smoking-related or alcohol-related cancer risk in men or women.