Global burden of rheumatoid arthritis among adolescents and young adults aged 10–24 years: A trend analysis study from 1990 to 2019
Authors: Li Ruibo , Yuan Xingyue , Ou Yili 
Published: April 2024

Background
In recent decades, there has been a global increase in the burden of rheumatoid arthritis (RA) among adolescents and young adults (AYAs), making it a significant public health issue. However, our understanding of the disease burden, harm, and influencing factors of RA in this population remains insufficient. This study aimed to assess the trends in RA burden among AYAs aged 10–24 years from 1990 to 2019 at the global, regional, and national levels.

Methods
Incidence, prevalence, and disability-adjusted life years (DALYs) rate per 100,000 population, as well as average annual percentage changes (AAPCs), of RA among individuals aged 10–24 years were reported globally, regionally, and nationally based on the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 (GBD 2019). These global trends were further analyzed by age, sex, and Sociodemographic index (SDI). Joinpoint regression analysis was used to determine the year in which the most significant changes in global trends occurred.

Results
Globally, the incidence of RA among AYAs increased from 4.98 per 100,000 population in 1990 to 5.41 per 100,000 population in 2019, with an AAPCs of 0.29 (95%CI: 0.26, 0.32, p < 0.001). The most significant increase occurred in 2000, while the most significant decrease occurred in 2014. The prevalence increased from 34.11 per 100,000 population in 1990 to 36.34 per 100,000 population in 2019, with an AAPCs of 0.22 (95%CI: 0.19, 0.24, p<0.001); The most significant increase was observed in 2000, and the most significant decrease occurred in 2014. DALYs rate with RA were 5.96 per 100,000 population in 1990 and 5.79 per 100,000 population in 2019 for AYAs, with an average decrease of 0.1 years per year (AAPCs = -0.1, 95%CI: -0.2, -0.01, p = 0.04). In terms of gender, the incidence, prevalence, and DALYs rate were higher for females compared to males during the same period. Regarding age, the incidence, prevalence, and DALYs rate increased with increasing age. Based on the SDI quintile, the incidence, prevalence, and DALYs rate of RA were highest in countries with high SDI and lowest in countries with low SDI from 1990 to 2019. However, the relationship between incidence and SDI is non-linear. In terms of regions, Tropical Latin America exhibited the highest incidence, prevalence, and DALYs rate, while Andean Latin America experienced the most rapid increase in incidence and prevalence. Southern Latin America saw the fastest growth in DALYs rate, whereas Southern Sub-Saharan Africa witnessed the most significant decline.

Conclusion
In conclusion, the study revealed an overall increase in the incidence and prevalence of RA among adolescents and young adults (AYAs) over the past three decades, while DALYs rate remained relatively stable. Furthermore, the incidence, prevalence, and DALYs rate of RA were found to increase with age. Fortunately, recent proactive preventive measures and treatment methods have shown promising results. Moving forward, it is crucial to prioritize the female population and AYAs patients in order to further alleviate the global burden of RA.