Non-alcoholic fatty liver disease (NAFLD) is increasingly common worldwide and has become the first cause of chronic liver disease. It is characterized by excessive accumulation of fat in the liver, associated with insulin resistance. NAFLD is defined by evidence of steatosis in ≥5% of hepatocytes according to histological analysis or imaging in the absence of secondary causes of hepatic fat accumulation such as significant alcohol consumption (daily consumption ≥30 g for men and ≥20 g for women, or >21 standard drinks on average per week in men and >14 standard drinks on average per week in women).
NAFLD can be subdivided into non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). Whereas NAFL (or steatosis) is defined as hepatic fat content of ≥5% of liver weight or ≥5% fat-loaded hepatocytes with no evidence of hepatocellular injury (ballooning) or fibrosis, NASH is characterized by hepatic steatosis ≥5%, inflammation and ballooned hepatocytes, with or without the presence of hepatic fibrosis.. NASH thereby covers a wide spectrum of disease severity in individuals without significant alcohol consumption and without other causes of secondary steatosis. NASH can progress to cirrhosis, liver failure and, more rarely, hepatocellular carcinoma (HCC).
|Disease||Definition and continuum|
– Entire spectrum of fatty liver disease in individuals without significant alcohol consumption
– From fatty liver to hepatic steatosis and to cirrhosis
– No evidence of hepatocellular injury (ballooning)
– No evidence of fibrosis
– Hepatic steatosis ≥ 5%
– Hepatocyte injury (ballooning)
– With or without fibrosis