Global cancer burden attributable to excess body weight, 1990 to 2021, decomposed by population size, aging, and epidemiological change

Objective: The objective of this study was to estimate cancer burden attributable to excess body weight (EBW) and identify its main source. Methods: We obtained relative risks from meta-analyses, cancer and population data from the Global Burden of Disease Study (GBD) 2021, and BMI prevalence data from the NCD Risk Factor Collaboration (NCD-RisC). We calculated the incidence of 11 cancers attributable to high BMI from 1990 to 2021, analyzed trends using joinpoint regression, and assessed cohort effects with the age-period-cohort model. Decomposition analysis was conducted by cancer-specific risk factors and by population size, aging, and epidemiological changes. Results: The incidence of 11 EBW-related cancers has increased from 1990 to 2021. Later-born cohorts and older age groups had higher cancer incidence rates. High BMI was the top contributor to changes in cancer burden (15.96% of all disability-adjusted life years [DALYs]), particularly in high Sociodemographic Index (SDI) regions. Colorectal, esophageal, and liver cancer had the highest burden due to high BMI (1,349,622; 1,284,385; and 944,616 DALYs, respectively). Epidemiological changes in BMI contributed to the rising DALY burden, ranging from 7.88% for postmenopausal breast cancer to 49.20% for liver cancer. Conclusions: The rising prevalence of EBW contributed to the global cancer burden, showing a significant birth cohort effect. High BMI was the top contributing factor to obesity-related cancers, surpassing other epidemiological risk factors. (Figure presented.).