Fatty liver disease affects nearly a third of Westerners, often silently
About 30 percent of people in Western countries have fat building up in their livers from metabolic causes, and most feel nothing at all. In June 2023 liver specialists renamed the condition, dropping non-alcoholic in favour of labels built around metabolic dysfunction, the main driver behind it.
Fatty liver disease, also called hepatic steatosis or steatotic liver disease, means excess fat accumulating in the liver. Symptoms are usually absent or mild, occasionally tiredness or pain under the right ribs. Over time it can lead to fibrosis, cirrhosis, liver cancer and swollen veins in the oesophagus.
There are two main forms. One is linked to alcohol: more than 90 percent of heavy drinkers develop fatty liver, and about a quarter progress to alcoholic hepatitis, partly because breaking down alcohol produces toxic compounds such as aldehydes. The other, now called MASLD, is tied to type 2 diabetes, obesity and the wider metabolic syndrome. Until 2023 it was known as NAFLD, and its inflamed, more serious form as NASH, now MASH. The renaming came from a modified Delphi process led by the American, European and Latin American liver associations, which also created metALD for people with MASLD who drink substantial but not heavy amounts.
MASLD affects about 10 percent of people in Asia and about 10 percent of American children, and is commoner in men and older people. Other risks include glucocorticoid drugs and hepatitis C, along with rarer causes such as some inherited metabolic disorders and acute fatty liver of pregnancy. Nobody yet knows why some people keep a simple fatty liver while others develop MASH, which carries worse outcomes. Non-obese people can be affected too, and are then at higher risk.
Diagnosis draws on medical history, blood tests, imaging and sometimes biopsy. Ten-year survival with MASLD has been put at about 80 percent. Fibrosis is estimated to advance one stage roughly every 7 years in MASH and every 14 in MASLD. Fewer than 10 percent of people with cirrhosis from alcohol develop the commonest adult liver cancer, but up to 45 percent of those with MASH can develop it even without cirrhosis. Treatment usually centres on weight loss through diet and exercise, with transplantation for the most severe cases.
Source: Fatty liver disease
