New cancer cases attributable to diet among adults aged 30-84 years in France in 2015.

This study aimed to estimate the number of new cancer cases attributable to diet among adults aged 30-84 years in France in 2015, where convincing or probable evidence of a causal association exists, and, in a secondary analysis, where at least limited but suggestive evidence of a causal association exists. Cancer cases attributable to diet were estimated assuming a 10-year latency period. Dietary intake data were obtained from the 2006 French National Nutrition and Health Survey. Counterfactual scenarios of dietary intake were based on dietary guidelines. Corresponding risk relation estimates were obtained from meta-analyses, cohort studies and one case-control study. Cancer incidence data were obtained from the French Network of Cancer Registries. Nationally, unfavourable dietary habits led to 16 930 new cancer cases, representing 5.4 % of all new cancer cases. Low intake of fruit and dietary fibre was the largest contributor to this burden, being responsible for 4787 and 4389 new cancer cases, respectively. If this is expanded to dietary component and cancer pairs with at least limited but suggestive evidence of a causal association, 36 049 new cancer cases, representing 11.6 % of all new cancer cases, were estimated to be attributable to diet. These findings suggest that unfavourable dietary habits lead to a substantial number of new cancer cases in France; however, there is a large degree of uncertainty as to the number of cancers attributable to diet, including through indirect mechanisms such as obesity, and therefore additional research is needed to determine how diet affects cancer risk.