Fatty liver disease

Fatty liver disease (FLD, also called steatotic liver disease) refers to excessive fat build-up in liver cells (hepatocytes).

Its main form is metabolic-associated steatotic liver disease (MASLD, formerly NAFLD), which is usually associated with metabolic factors such as obesity, type-2 diabetes, hypertension, lipid disorders and metabolic syndrome. Alcoholic fatty liver is associated with excessive alcohol consumption. Other forms of fatty liver can be caused by taking medications (such as methotrexate), genetic disease or viral infections.

MASLD is very common, affecting about 25%–30% of the world’s population; its prevalence is even higher in people with diabetes or obesity.

There are several stages of MASLD:

1. Simple steatosis: fat build-up with no significant inflammation.
2. Metabolic-associated steatohepatitis (MASH, formerly NASH): inflammation and liver damage.
3. Fibrosis: formation of scar tissue in the liver.
4. Cirrhosis: advanced destruction of the liver, which can lead to serious complications (liver failure, liver cancer).

Blood tests (AST, ALT, FIB-4, ELF) and imaging techniques such as impulse elastography (FibroScan) are used to detect steatotic liver disease. In some cases, a liver biopsy may be necessary.

Treatment depends on progression, but is based on lifestyle changes: weight loss, physical activity, balanced diet, giving up alcohol. No specific drugs have been approved in Canada so far, although some have been approved in other countries.