Global age-specific burden of HBV-related diseases, 1990–2021, with projections to 2050

BACKGROUND: Universal childhood vaccination has contributed to reductions in hepatitis B virus (HBV)-related disease burden among younger populations, but population aging is increasing it in older adults. This study assesses age‑specific global HBV-related disease trends (1990-2021), quantifies drivers, and projects to 2050 to inform optimized prevention strategies. METHODS: We used Global Burden of Disease 2021 data to analyze trends in incidence, prevalence, deaths, and disability-adjusted life-years (DALYs) for HBV-related diseases from 1990-2021. We stratified analyses by age groups (< 20, 20-54, ≥ 55 years). We quantified contributing drivers using Das Gupta decomposition and mapped geographic patterns by socio-demographic index (SDI). We applied Bayesian age-period-cohort modeling to project future burden through 2050. RESULTS: From 1990 to 2021, global age-standardized incidence, prevalence, death, and DALY rates of HBV-related diseases declined, whereas the absolute numbers of deaths and DALYs increased. Age-stratified analyses showed sharp declines in all burden indicators among individuals < 20 years, while reductions were modest and case numbers increased among those aged 20-54 and, more prominently, ≥ 55 years. Decomposition analysis demonstrated that epidemiological improvements drove reductions in younger populations, whereas population growth and aging offset these gains in older adults. Geographically, the highest burden remained concentrated in sub-Saharan Africa and Southeast Asia, while high SDI regions maintained the lowest levels. Relative changes indicated substantial global incidence reductions in the < 20 years group, with smaller declines in older groups. Projections suggest that although overall rates will continue to decline, the absolute burden in the ≥ 55 years group will continue to rise through 2050. CONCLUSIONS: Although HBV-related disease burden continues to decline among younger populations, population growth and aging are reshaping the global HBV burden toward individuals aged ≥ 55 years, highlighting the need for targeted prevention and management strategies.