Cancer cases attributable to modifiable lifestyle risk factors in Switzerland between 2015 and 2019.

Several modifiable lifestyle risk factors have been linked to higher cancer risk in the literature. Determining the proportion and number of cancer cases attributable to these risk factors is pivotal in informing effective cancer prevention and control plans that have the greatest effect on reducing cancer incidence. We aimed to estimate the proportion and number of incident cancer cases that were attributable to modifiable lifestyle risk factors (ie, tobacco smoking, high alcohol consumption, excess body weight, physical inactivity and unhealthy diet) in Switzerland between 2015 and 2019. The exposure prevalence of selected risk factors was estimated based on the representative national nutrition survey menuCH, the associated relative risks were obtained from systematic literature reviews and the numbers of incident cancer cases were provided by the National Institute for Cancer Epidemiology and Registration. The fractions and numbers of attributable cases were calculated overall, by sex and by the three major language regions of Switzerland. The investigated modifiable risk factors combined were linked to 25.2% of potentially preventable incident cancer cases in Switzerland between 2015 and 2019. The proportion and numbers were slightly larger in males (28.4%, 6945 cases per year) than in females (21.9%, 4493 cases per year), and variations were observed between language regions. Tobacco smoking, excess body weight and high alcohol consumption were the leading contributors to lifestyle-attributable cancer cases. The observed differences in the leading risk factors both within Switzerland and compared to other countries underline the need for regionally and nationally tailored cancer prevention and education strategies.