Prevalence of Nonalcoholic Steatohepatitis in Iran: A Population based Study

BACKGROUND Non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) is the most common form of chronic liver disease worldwide and is no longer considered a benign disease. Its prevalence has not been determined in a large-scale population-based study in Iran. METHODS A total of 6583 individuals aged 18 to 65 were randomly selected from three geographically distinct provinces in Iran. Blood samples were obtained from each subject and a questionnaire was completed exploring data including self-admitted regular alcohol use. Serums were tested for anti-HCV antibody (anti-HCV), hepatitis B surface antigen and anti-hepatitis B core antibody. Positive samples for anti-HCV antibody were re-tested and those positive in a repeat ELISA were confirmed by a recombinant immunoblot assay (RIBA) test. Serums were also tested for ALT levels. Subjects with elevated ALT defined as serum ALT ≥40 IU/L with no history of alcohol consumption and negative HBV and HCV infection were considered as "presumed NASH". RESULTS In this study 5589 subjects were analyzed. Two hundred and forty two individuals (4.3%) were diagnosed with elevated ALT levels. Among individuals with elevated ALT, 15 (6.2%) were diagnosed with either hepatitis B or hepatitis C. The overall weighted prevalence of presumed NASH was 2.9%. According to multivariate analysis, male sex, urban lifestyle, and being overweight or obese were significantly associated with "presumed NASH". CONCLUSION Obesity and metabolic syndrome, the most predictive factors of fatty liver disease, are increasing in Iran, therefore the prevalence of NAFLD/NASH and related complications are expected to increase in the future. This population based study gives a crude estimate of the prevalence of NASH around the country. Studies with more accurate surrogates of NASH need to be done. The disparity among different provinces merits special consideration.