Metabolic dysfunction-associated steatotic liver disease (MASLD, formerly known as non-alcoholic fatty liver disease, or NAFLD) and metabolic dysfunction-associated steatohepatitis (MASH, formerly known as non-alcoholic steatohepatitis, or NASH) are caused by fat accumulation in the liver, known as hepatic steatosis. Heavy alcohol consumption can also lead to fat accumulation, a condition known as alcohol-related liver disease (ALD). Together, they fall under the umbrella of steatotic liver disease (SLD).
The buildup of fat in the liver can lead to inflammation, fibrosis, cirrhosis and hepatocellular carcinoma (HCC), the most common type of primary liver cancer.
Linked to obesity and type 2 diabetes, steatotic liver disease is increasingly recognized as a metabolic disorder. Many experts consider it part of metabolic syndrome, a cluster of conditions that raise the risk for cardiovascular disease and other health problems.
Steatotic liver disease is responsible for a growing burden of advanced liver disease in the Uited States and worldwide, coinciding with rising rates of obesity. Estimates suggest that around one third of Americans have MASLD, but many remain undiagnosed. Even children and adolescents are increasingly being diagnosed with fatty liver disease.
Now that vaccines can prevent hepatitis B and antiviral therapy can easily cure hepatitis C, steatotic liver disease is a leading cause of cirrhosis liver cancer and liver transplants.
Last Reviewed: November 13, 2023
