Non-alcoholic fatty liver disease (NAFLD) is one of the causes of fatty liver, occurring when fat is deposited (steatosis) in the liver due to causes other than excessive alcohol use. NAFLD is the most common liver disorder in developed countries.Estimated prevalence of 20%-50% in the general population and is tightly associated with metabolic syndrome. The estimated prevalence of nonalcoholic steatohepatitis (NASH) is 2%-9%. A higher prevalence is observed among diabetics and obese individuals.
Common findings are elevated liver enzymes and a liver ultrasound showing steatosis. An ultrasound may also be used to exclude gallstone problems (cholelithiasis). A liver biopsy (tissue examination) is the only test widely accepted as definitively distinguishing NASH from other forms of liver disease and can be used to assess the severity of the inflammation and resultant fibrosis.NAFLD typically shows up as an unexpected abnormality in liver function tests, usually the alanine aminotransferase (ALT) test, in people who otherwise feel well. The elevation of this test generally is minor and in younger patients, does not indicate a serious liver condition. However, if the cause of NAFLD, such as obesity or diabetes, is not treated, the condition may progress.