A significant and persistent rise in the global burden of adolescent NAFLD and NASH estimated by BMI.

Background: Currently, there is a lack of global or even country/regional level data on adolescent non-alcoholic fatty liver disease (NAFLD) prevalence. However, an evidenced dose-dependent relationship exists between body mass index (BMI) and the risk of NAFLD. We aim to estimate the global and regional prevalence of adolescent NAFLD and related non-alcoholic steatohepatitis (NASH) based on BMI. Methods: Sigmoidal fitting curves were generated between BMI and the risk of NAFLD/NASH using the data extracted from the NHANES database. With global and regional BMI data from the NCD-RisC database, adolescent NAFLD/NASH prevalence was estimated at the international, regional, and country levels from 1975 to 2016. The prevalence of adolescent NAFLD/NASH from 2017 to 2030 was also forecasted. Results: The mean NAFLD prevalence was 15.31, and 12.68%, while the mean NASH prevalence was 2.50, and 2.47%, in boys, and girls aged 12-18, respectively. For both boys and girls, NAFLD/NASH prevalence increased with increasing BMI, and age. The global prevalence of adolescent NAFLD/NASH has gradually increased in the period from 1975 to 2016 and will maintain a similar trend between 2017 and 2030. High-income Western Countries had higher adolescent NAFLD/NASH whereas South Asia and Sub-Saharan Africa exhibited relatively lower adolescent NAFLD/NASH prevalence. The estimated annual percentage change (EAPC) of NAFLD prevalence in boys ranged from 0.72% (age 18) to 1.16% (age 12) while that in girls ranged from 0.69% (age 18) to 0.92% (age 12). EAPC of NASH prevalence in boys ranged from 1.65% (age 18) to 1.77% (age 12), and in girls from 1.48% (age 18) to 1.68% (age 12). Conclusion: The adolescent NAFLD/NASH prevalence increases year by year, and its burden varies significantly among different countries and regions. BMI is a precise predictor of NAFLD/NASH prevalence.