Global, regional, and national burdens of early onset gastric cancer aged 15–49 years from 1990 to 2021 with projections to 2035: a population-based study

BACKGROUND: Early-onset gastric cancer (EOGC) is a distinct clinical entity with unique epidemiological and pathological features. Despite an overall decline in GC incidence in many regions, recent studies have shown an increasing trend in EOGC incidence in some areas. This study aims to systematically evaluate the global, regional, and national burden of EOGC from 1990 to 2021 using data from the Global Burden of Disease (GBD) 2021 study. METHODS: Data on the incidence, mortality, and disability-adjusted life-years (DALYs) of EOGC were obtained from the GBD 2021 database. The age-standardized incidence rates (ASIRs), age-standardized mortality rates (ASMRs), and age-standardized DALYs rates (ASDRs) were calculated. Estimated annual percentage change (EAPC) was used to assess temporal trends. The Bayesian age-period-cohort model was employed to project trends up to 2035. RESULTS: Globally, the ASIR of EOGC decreased from 5.40 per 100,000 in 1990 to 3.17 per 100,000 in 2021 (EAPC -1.8, 95% CI: -1.9 to -1.7). The ASMR decreased from 2.00 per 100,000 in 1990 to 1.31 per 100,000 in 2021 (EAPC -2.4, 95% CI: -2.5 to -2.3), and the ASDR decreased from 97.73 per 100,000 in 1990 to 63.98 per 100,000 in 2021 (EAPC -2.5, 95% CI:-2.6 to -2.4). East Asia had the highest ASIR, ASMR, and ASDR. Regions with higher Socio-demographic Index (SDI) values experienced more significant declines in EOGC incidence and mortality. High-sodium diets and smoking were identified as significant risk factors. Forecasts toward 2035 indicate a continued decline in ASIR, ASMR, and ASDR globally. CONCLUSIONS: Despite a decrease in ASIR, ASMR, and ASDR globally, the absolute burden of EOGC remains high, with significant regional disparities. Targeted prevention and treatment strategies are needed, particularly in low- and middle-income countries. Future research should focus on identifying additional risk factors and exploring the effectiveness of different preventive strategies in various regions.