Global, regional, and national burden and trends of bladder cancer in individuals aged 55 years and older from 1990 to 2021: findings from the Global Burden of Disease Study 2021

BACKGROUND: Bladder cancer (BC), a prevalent genitourinary malignancy, poses a substantial threat to public health, particularly among middle-aged and elderly populations. Given the increasing life expectancy, understanding the BC burden in these demographic groups is imperative. METHODS: Based on the GBD 2021 dataset encompassing 371 diseases and injuries with 88 risk factors globally, this study analyzed bladder cancer data from 204 countries and territories (1990-2021) for populations aged ≥55 years, with core metrics including incidence, deaths, and disability-adjusted life years (DALYs). We used Joinpoint regression analysis to assess temporal trends, calculating the Annual Percentage Change (APC) and Average Annual Percentage Change (AAPC). We conducted a decomposition analysis to break down the changes in mortality rates into contributions from aging, population growth, and epidemiological changes. We performed a frontier analysis using the Socio-demographic Index (SDI) to evaluate the relationship between bladder cancer burden in people aged 55 and above and socio-demographic development. Among them, we further combined the National Health and Nutrition Examination Survey (NHANES) database for risk analysis related to bladder cancer. Finally, we used the Bayesian age-period-cohort (BAPC) model to project bladder cancer trends from 2022 to 2036. RESULTS: From 1990 to 2021, bladder cancer cases among adults ≥55 years increased by 113% (226 421 to 483 234), while crude incidence rates declined slightly. Mortality rates decreased from 16.83 to 14.11 per 100 000, and DALYs rates dropped from 337.59 to 257.76. High-income regions (North America: 76.85/100 000; Western Europe: 77.62/100 000) had the highest incidence but showed downward trends, whereas Central Europe experienced rising mortality. Males consistently bore a 3.8-fold higher incidence burden than females. Smoking (26.6%) and high fasting glucose (8.2%) were key risk factors. According to NHANES data, elevated fasting blood glucose levels and smoking are both associated with an increased risk of bladder cancer. Projections to 2036 suggest continued declines: incidence (-13.3%), mortality (-16.4%), and DALYs (-17.9%). Health inequality persisted but improved marginally. CONCLUSION: The current data and future prediction of this study show that the incidence rate, mortality and DALYs rate of bladder cancer in middle-aged and elderly people have declined. However, disparities in disease burden still exist across regions. Thus, tailored measures are needed to reduce inequalities in high-burden areas.