Changing epidemiology, global trends and implications for outcomes of NAFLD

Non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common liver disease globally, currently estimated to affect 38% of the global population. A minority of patients with NAFLD will progress to cirrhosis or hepatocellular carcinoma, but the total number of this vast population that risk such severe outcomes is increasing. Worryingly, persons are affected by NAFLD at an earlier age, suggesting they have longer time to develop severe complications. With considerable changes in diet composition and urbanization, obesity and type 2 diabetes among the global population, in particular in developing countries, the global proportion of persons affected by NAFLD is projected to be further increasing. Yet, there are large geographical discrepancies in the prevalence rates of NAFLD and its inflammatory component non-alcoholic steatohepatitis (NASH). Such differences are partly related to differing socio-economic milieus, but also to genetic predisposition.This narrative review discusses recent changes in the epidemiology of NAFLD and NASH from regional and global perspectives, as well as in special populations. We also discuss the consequences these changes can have on hepatic and extra-hepatic events.