The Global Epidemiology of Nonalcoholic Steatohepatitis (NASH) and Associated Risk Factors – A Targeted Literature Review

Abstract Background : There is a wide variation across studies in the reported prevalence of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). A targeted literature review was conducted to understand the prevalence of NALFD and NASH in the general population and specific sub-populations as well as identify risk factors associated with NASH Methods : Embase and Medline databases (2003–July 2018, English language) and relevant conferences were searched to identify observational studies and meta-analysis reporting outcomes of interest. Small cohort studies ( Results : A total of 32 studies were included. Prevalence of NAFLD among general population ranged from 11.2% to 37.2% in the reviewed studies. Similar wide ranges were shown in the frequency of biopsy-confirmed NASH among NAFLD patients ranging from 15.9% to 68.3%. The prevalence of NAFLD and NASH among type 2 diabetes mellitus (T2DM) patients was 54% and 65.26%, respectively. Frequency of NASH ranged from 12.6% to 30.4% among the obese patients. The rate of disease progression was associated with age, ethnicity, genetics, and presence of comorbidities (e.g. obesity, T2DM, and hypertension) Conclusions : The review highlighted significant variability in the reported prevalence globally, further emphasizing the need to achieve consensus in terminology, disease definition, and diagnostic methods to determine the actual prevalence of NAFLD and NASH.