Compared to the 2000s, NAFL and NASH respectively increased 2-fold and 2.5-fold in the 2010s in the USA.NAFLD and NASH are more prevalent in Hispanics - which can be attributed to high rates of obesity and type 2 diabetes in Hispanic populations, intermediate in Whites, and lowest in Blacks. NAFLD was observed to be twice as prevalent in men as women. For severely obese individuals, the prevalence of NAFLD rises over 90%, and for those with diabetes, over 60%, and up to 20% for normal-weight people. NAFLD is present in 65% to 90% of people that had bariatric surgery, and up to 75% of them have NASH. Ultrasonography and proton NMR spectroscopy studies suggest about 25% of the population seems to be affected by NAFLD or NASH.Although the disease is commonly associated with obesity, a significant proportion of those affected are normal weight or lean. Lean NAFLD affects between 10 and 20% of Americans and Europeans, and approximately 25% of the Asians, although some countries have a higher incidence (e.g., India has a very high proportion of lean NAFLD and almost no obese NAFLD). PNPLA3 may be relevant for the progression of NAFLD in lean people. Thus, people with NAFLD deserve consideration for treatment regardless of the presence or absence of obesity.In children ages 1 to 19, the prevalence was found to be approximately 8% in the general population up to 34% in studies with data from child obesity clinics.The majority of cryptogenic cirrhosis is believed to be due to NASH.
Non-alcoholic fatty liver disease (NAFLD), also known as metabolic (dysfunction) associated fatty liver disease (MAFLD), is excessive fat build-up in the liver without another clear cause such as alcohol use. There are two types; non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH), with the latter also including liver inflammation. Non-alcoholic fatty liver is less dangerous than NASH and usually does not progress to NASH or liver cirrhosis. When NAFL does progress to NASH, it may eventually lead to complications such as cirrhosis, liver cancer, liver failure, or cardiovascular disease.Obesity and type 2 diabetes are strong risk factors for NAFLD. Other risks include being overweight, metabolic syndrome (defined as at least three of the five following medical conditions: abdominal obesity, high blood pressure, high blood sugar, high serum triglycerides, and low serum HDL cholesterol), a diet high in fructose, and older age. NAFLD and alcoholic liver disease are types of fatty liver disease. Obtaining a sample of the liver after excluding other potential causes of fatty liver can confirm the diagnosis.Treatment for NAFLD is weight loss by dietary changes and exercise. There is tentative evidence for pioglitazone and vitamin E; bariatric surgery can improve or resolve severe cases. Those with NASH have a 2.6% increased risk of dying per year.NAFLD is the most common liver disorder worldwide and is present in approximately 25% of the worlds population. It is also very common in developed nations, such as the United States, and affected about 75 to 100 million Americans in 2017.