Disease burden of rheumatoid arthritis in the context of population aging: A comparative analysis of China, Japan, the United States and India
Si Yang, Jiashun ZengAbstract
Background and Objectives
As worldwide population aging accelerates, the burden of rheumatoid arthritis (RA) continues to increase. This study compared the spatiotemporal trends and underlying drivers of the RA burden across four countries with different levels of socioeconomic development under population aging.
Methods
Using data from the Global Burden of Disease (GBD) 2021 study, we analyzed age-standardized rates of incidence, prevalence, mortality, and disability-adjusted life years (DALYs) for RA in China, Japan, the United States, and India from 1990 to 2021. Temporal trends were assessed using Joinpoint regression. A decomposition model was applied to quantify the contributions of population growth, population aging, and epidemiological changes to the overall burden. Spearman correlation analysis was performed to evaluate the association between RA burden indicators and the Sociodemographic Index (SDI). The Nordpred model was employed to project age-standardized prevalence rates among individuals aged 60 years and older up to 2046.
Results
From 1990 to 2021, the numbers of incident cases, prevalent cases, and DALYs attributable to RA increased substantially in China, the United States, and India ( e.g ., prevalent cases in China rose from 2.04 million to 4.76 million, and DALYs increased from 403,000 to 834,000), whereas the corresponding trends in Japan remained relatively stable. Age-standardized DALY rates increased significantly in China and India but exhibited a declining trend in Japan. Decomposition analysis revealed that the rise in RA burden in China was jointly driven by population aging and population growth, while in Japan, population aging alone accounted for nearly the entire increase. RA prevalence showed a strong positive correlation with SDI ( r = 0.82, P < 0.001). Projections indicate that by 2046, the age-standardized prevalence of RA among older adults will continue to rise in China, the United States, and India, whereas Japan is expected to reach a plateau.
Conclusion
The burden of RA remains substantial in China, the United States, and India, and has shown a continuous upward trend, with older women being at particularly high risk. Population aging and population growth are the main driving factors. These findings highlight the need to establish a targeted comprehensive prevention and control system for RA among older adults and formulate differentiated, forward-looking health policies aligned with population aging trends to mitigate the future disease burden.