摘要Objective:This study aimed to assess the global,regional,and national burden of early-onset gastric cancer(EOGC)and the attributable risk factors from 1990-2021 with projections extending to 2040.Methods:The EOGC burden was quantified using incidence,prevalence,mortality,and disability-adjusted life years(DALYs)with calculation of age-standardized rates.The risk factor contributions were analyzed and disparities were evaluated using the slope index of inequality.Future trends for 2021-2040 were estimated using a Bayesian age-period-cohort model.Results:There were approximately 125,000 new cases of EOGC globally in 2021 with an estimated 336,000 individuals living with EOGC and 78,000 associated deaths,contributing to 3.86 million DALYs.The highest EOGC incidence rates existed among individuals 45-49 years of age.The global age-standardized incidence,prevalence,mortality,and DALY rates demonstrated an overall decline between 1990 and 2021.Smoking and high-salt dietary intake were the leading risk factors for DALYs with regional and gender-based variations.Smoking accounted for＞10％of DALYs in Central Europe and East Asia,while high-salt dietary intake accounted for approximately 8％of DALYs.Despite the overall decline in the EOGC burden,disparities across geographic regions widened.Projections indicated a continued gradual reduction in EOGC burden through 2040.Conclusion:Although the global burden of EOGC has decreased,significant disparities persist across geographic regions,age groups,and genders.Public health interventions should combine smoking prevention strategies(e.g.,youth education and tobacco taxation)with cessation programs with dietary salt reduction initiatives.