Global 30-Year Trajectory and Socioeconomic Disparities of Type 2 Diabetes Mellitus in Older Adults (1990–2021)

Background: Type 2 diabetes mellitus (T2DM) is an escalating global health crisis among aging populations, warranting a comprehensive epidemiological assessment to support evidence-based policy development. Methods: Using data from the Global Burden of Disease Study 2021, we examined age-standardized rates of prevalence, incidence, mortality, and disability-adjusted life-years among populations aged ≥55 years from 1990 to 2021. Temporal patterns were quantified using estimated annual percentage change (EAPC). Decomposition analysis was used to identify drivers of burden change, and Bayesian age-period-cohort models were used to project trends through 2040. Results: Global T2DM cases among adults aged ≥55 years reached 305.6 million in 2021 (95% uncertainty interval, 282.3-331.7 million), representing a 244% increase since 1990. The age-standardized prevalence rate reached 19,298.52 per 100,000, with a sustained upward trajectory (EAPC: 1.217; 95% confidence interval, 1.172 to 1.262). Regional disparities were pronounced, ranging from 32,846.21 per 100,000 in North Africa and the Middle East to 10,400.58 per 100,000 in Eastern Sub-Saharan Africa. Males and populations in low-middle-income region experienced a disproportionately high burden. Risk factor analysis identified high body mass index as the dominant contributor (46.0%), followed by ambient particulate matter pollution (11.8%) and low physical activity (8.8%). Projections indicate continued increases in prevalence rates to 25,706.8 and 21,693.4 per 100,000 in men and women, respectively, by 2040. Conclusion: The T2DM burden among older adults has expanded dramatically, revealing substantial regional and socioeconomic disparities. These findings underscore the urgent need for evidence-based interventions targeting obesity prevention and age-specific healthcare frameworks.