Global, regional, and national epidemiology of osteoarthritis in working-age individuals: insights from the global burden of disease study 1990-2021.

Osteoarthritis (OA) is a chronic degenerative joint disease with an increasing global burden, particularly among the working-age population. This study aims to analyze the temporal trends in OA burden by age and sex globally from 1990 to 2021, focusing on incidence, prevalence, and disability-adjusted life years (DALYs) rates, and to predict future trends. Using data from the Global Burden of Disease (GBD) database, which includes 204 countries and regions, we stratified the findings by the sociodemographic index (SDI). Age-standardized rates were used to calculate the estimated annual percentage change (EAPC) with corresponding 95% confidence intervals (95% CI). Additionally, a Bayesian Age-Period-Cohort (BAPC) model was employed to project future OA trends up to 2040.The results revealed a consistent increase in the global OA burden over the study period. Between 1990 and 2021, the number of OA cases in the working-age population increased from 16,420,160 to 35,494,218, representing a growth rate of 116.16%. Over the same period, prevalence and DALYs rose by 123.11% and 125%, respectively. Global age-standardized incidence rate (ASIR), prevalence rate (ASPR), and DALYs rate (ASDR) exhibited continuous upward trends, with annual percentage changes of 0.387%, 0.431%, and 0.46%, respectively. Notably, East Asia demonstrated the highest EAPC, reflecting a rapid rise in OA burden, while high-income North America exhibited minimal changes, indicating a relatively stable trend. Countries such as Equatorial Guinea, Mongolia, and Armenia also experienced significant increases in EAPC, underscoring emerging regional challenges.Further socioeconomic analysis highlighted disparities in OA burden. A significant positive correlation was observed between ASIR, ASPR, ASDR, and SDI. While low-SDI countries exhibited lower OA burdens, metrics were substantially higher in high-SDI countries. From 1990 to 2021, the gap between countries with the highest and lowest SDIs widened, underscoring growing global health inequalities. Projections based on the BAPC model suggest that by 2040, the incidence and prevalence of OA will continue to rise, with the number of cases expected to reach 38,800,395, particularly driven by notable increases among women.These findings highlight the urgent need for developing targeted public health strategies to mitigate the effect of OA on the working-age population and promote global health equity.