A GBD 2021-Based Analytical Workflow to Estimate the Global Burden of Neoplasms Attributable to Low Physical Activity

This protocol describes a reproducible analytical workflow for estimating the global burden of neoplasms attributable to low physical activity using Global Burden of Disease 2021 data. The workflow includes data extraction from the GBD Results Tool, definition of eligible outcomes and exposure categories, estimation of deaths, disability-adjusted life years, and age-standardized rates, temporal trend analysis using estimated annual percentage change and joinpoint regression, decomposition analysis, socioeconomic inequality assessment, and Bayesian age-period-cohort projection. The protocol also describes how to interpret uncertainty intervals, decomposition components, and inequality metrics in the context of modeled population-level estimates. As a representative application, the workflow was applied to colorectal cancer and female breast cancer attributable to low physical activity across 204 countries and territories from 1990 to 2021, with projections to 2045. This protocol can be adapted for other GBD risk-outcome pairs when researchers need a structured approach for risk-attributable burden estimation, trend characterization, inequality assessment, and projection analysis.