Impact of population ageing on cancer-related disability-adjusted life years: A global decomposition analysis.

Background: As the global population ages, the burden of cancer is increasing. We aimed to assess the impact of population ageing on cancer-related disability-adjusted life years (DALYs). Methods: We used the decomposition method to estimate the impact of ageing, population growth, and epidemiological change on cancer-related DALYs from 1990 to 2019, stratified by 204 countries/territories and by their sociodemographic index (SDI). This approach separates the net effect of population ageing from population growth and change in age-specific DALY rates. Results: Cancer-related DALYs among individuals aged ≥65 years increased by 95.14% between 1990 (52.25 million) and 2019 (101.96 million). Population growth was the main contributor to cancer-related DALYs (92.38 million, attributed proportion: 60.91%), followed by population ageing (41.38 million, 27.28%). Cancer-related DALYs attributed to population ageing followed a bell-shaped pattern when stratified by SDI, meaning they peaked in middle-SDI countries. Cancer-related DALYs attributed to ageing increased in 171 and decreased in 33 countries/territories. The top three cancer types with the highest increase in the absolute number of cancer-related DALYs associated with ageing were tracheal, bronchus, and lung (8.72 million); stomach (5.06 million); and colorectal (4.28 million) cancers, while the attributed proportion of DALYs was the highest in prostate (44.75%), pancreatic (40.93%), and non-melanoma skin (38.03%) cancers. Conclusions: Population ageing contributed to global cancer-related DALYs, revealing a bell-shaped pattern when stratified by socioeconomic development, affecting middle-SDI countries the most. To respond to the growing ageing population and reduce cancer-related DALYs, it is necessary to allocate health care resources and prioritize interventions for older adults.