Global Burden of Non-alcoholic Fatty Liver Disease (NAFLD) and chronic liver disease (CLD) Among Adolescents and Young Adults.

BACKGROUND AND AIM The causes of chronic liver disease (CLD) among adults have changed. Data are lacking on trends among youth. We determined the trends and changes in the global burden of CLD among adolescents and young adults using Global Burden of Disease (GBD) data (2009-2019). APPROACH AND RESULTS The GBD study estimation methods were used to assess CLD prevalence, incidence, and deaths (21 GBD regions). Annual percent change (APC) calculation by Joinpoint regression modeling. Age groups were 15-19; 20-24, and 25-29 years old. Globally in 2019, the 15-29 group accounted for 17.2% (0.29 billion) of CLD prevalent cases, 11.2% (n= 232,072) CLD incident cases, and 3.8% (n=55,515) CLD deaths. Between 2009 to 2019, CLD prevalence rate increased annually among 25-29 (APC=+0.41%, p<.001); remained stable among 20-24 (APC=+0.02%, p=.582); and decreased among 15-19 (APC=-2.13%, p<.001). CLD prevalence increases were driven by the proportion with NAFLD (15-19- 40.8% to 52.9%, p<.001); 20-24-57.6% to 62.7%. p<.001); 25-29- 66.9% to 70.1%, p<.001); the proportion with HBV decreased across all age groups. NAFLD prevalence worsening trend (APC ≥ 0%) was global. Overall CLD death rate decreased annually in all age groups, driven by the decrease in the proportion with HBV [aged 15-19 (from 5.90% to 5.20%, p<.001); aged 20-24(from 18.62% to 16.37%. p<.001); and aged 25-29 (from 28.69% to 25.28%, p<.001)]; from 2015-2019, CLD death rate for HCV (APC=+1.46%) and NAFLD (APC=+2.26%) increased. CONCLUSION Over the past decade, the causes of CLD among 15-29-year-olds have shifted- viral hepatitis remains the most common cause of CLD deaths but the global burden of HBV incidence is decreasing while NAFLD is the main driver for increased CLD incidence.