Potential reduction of global colorectal cancer, 1990-2021.

Objectives: Primary prevention targeting modifiable risk factors would reduce the global burden of colorectal cancer, but the quantitative results are uncertain. We aimed to assess the global burden of colorectal cancer attributed to modifiable lifestyle factors and quantify the potential increase in life expectancy resulting from the elimination of these risk factors. Methods: Based on the Global Burden of Disease Study 2021, we examined colorectal cancer deaths and disability-adjusted life years attributed to modifiable risk factors (including smoking, diet low in whole grains, diet low in milk, diet high in red meat, diet low in calcium, diet high in processed meat, and diet low in fiber) at the global, regional, and national levels from 1990 to 2021. The abridged period life table method was utilized to quantify the potential gain in life expectancy from eliminating these risk factors. Results: Globally in 2021, 57.1 % of colorectal cancer deaths and 56.4 % of disability-adjusted life years were preventable, with rates of 7.55 (4.94-9.64) and 174.67 (114.54-222.24) per 100,000 population, respectively. The modifiable burden has diminished in the high, high-middle, and low socio-demographic index quintiles and remained steady in the middle one. However, there is a concerning increase in the low-middle one. In 2021, the elimination of global colorectal cancer attributed to modifiable factors would increase the life expectancy for males and females by 0.107 and 0.109 years, respectively. Conclusion: Our results quantitatively demonstrate the substantial burden reduction in colorectal cancer and the significant gain in life expectancy that can be achieved by eliminating modifiable lifestyle factors.