What is NASH?

Non-alcoholic fatty liver disease (NAFLD) occurs when an excess of fat lipids is stored in liver cells. [This is called steatosis] Nonalcoholic Steatohepatitis (NASH) is an advanced form of NAFLD in which tissue inflammation and liver cell damage is underway. [This is called steatohepatitis] NASH resembles alcoholic liver damage, but often occurs in people that do not consume alcohol. If left untreated, NASH can worsen, resulting in fibrosis, cirrhosis, liver cancer and eventually liver failure.

The National Institutes of Health estimates that 30 to 40 percent of adults in the U.S. have NAFLD and between 3 to 12 percent of adults have NASH.[1] Demographic studies also indicate that NAFLD and NASH are more common in Hispanics and non-Hispanic white populations that other minorities.[2] These conditions also affect children—studies estimate that about 10 percent of U.S. children could have NAFLD.[3] Other comorbidities are also common in NASH patients, including hypertension, diabetes, obesity and dyslipidemia—cardiovascular complications in particular may be strongly impactful for liver-related morbidity.[4]

Once progression to NASH is underway, patients come under increased risk for harmful liver diseases. Fibrosis in the liver, or the accumulation of scarred liver tissue, affects roughly one-third of NASH patients. Twenty-five percent of NASH patients develop cirrhosis, or significant improper liver functioning, within 9 years. When cirrhosis finally results in decompensation of the liver, the median survival rate drops to approximately two years. NASH is currently the second-highest cause of end-stage liver disease and hepatocellular carcinoma and is likely to rise to number one in 2-3 years.[5] By 2020, NASH also will overtake Hepatitis C as the leading cause of liver transplants in America.[6]

There are no symptoms early in the disease’s prognosis. In fact, many patients remain undiagnosed until the condition worsens and irreversible liver damage starts to occur. Eventually, those with NASH may begin to feel fatigue or weakness, experience unexplainable weight loss, and develop an ache in the upper right portion of their abdomen. Diagnosing NASH often involves performing multiple tests, such as blood testing, abdominal ultrasounds, CT scans, MRIs, PET scans and liver biopsies.

Treatment options remain limited to managing the condition, as no effective pharmaceutical treatment for NASH currently exists. Doctors recommend weight loss, exercise, quitting alcohol, cholesterol reduction, and controlling diabetes as ways to curtail the impacts of NASH.

The NASH Alliance is a coalition supporting federal policy advances and education to address this substantial unmet medical need.


[1] U.S. Department of Health and Human Services National Institute of Diabetes and Digestive and Kidney Diseases. Updated November 2016. https://www.niddk.nih.gov/health-information/liver-disease/nafld-nash/definition-facts

[2] Schneider, A. L., et al. Racial differences in nonalcoholic fatty liver disease in the U. S. population. Obesity 22, 292–299 (2014). Sherif, Z. A. et al. Global epidemiology of nonalcoholic fatty liver disease and perspectives on US minority populations. Dig. Dis. Sci. 61, 1214–1225 (2016). Saab, S., et al. Nonalcoholic fatty liver disease in Latinos. Clin. Gastroenterol. Hepatol. 14, 5–12 (2016). Benedict M, Zhang X. Non-alcoholic fatty liver disease: An expanded review. World Journal of Hepatology. 2017;9(16):715-732.

[3] Fussilo S, Rudolph B. Nonalcoholic fatty liver disease. Pediatrics in Review. 2015;36(5):198–206

[4] Younossi, Z. M. et al. Global epidemiology of nonalcoholic fatty liver disease — meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology 64, 73–84 (2016). Tapper, E.B. and Loomba, R., Nonalcoholic fatty liver disease, metabolic syndrome, and the fight that will define clinical practice for a generation of hepatologists. Hepatology, 67: 1657-1659 (2018).

[5] Mohamad, B., et al., Characterization of hepatocellular carcinoma (HCC) in non-alcoholic fatty liver disease (NAFLD) patients without cirrhosis. Hepatol Int 10(4) 632-9 (2016).

[6] Parikh, N. D., et al, Projected increase in obesity and non‐alcoholic‐steatohepatitis–related liver transplantation waitlist additions in the United States. Hepatology (2017)


Twenty-five percent of NASH patients develop cirrhosis, or significant improper liver functioning, within 9 years.

Steatosis; occurs when an excess of fat lipids are stored in liver cells.

Healthy Liver (left) and Liver with Cirrhosis (right).

Steatohepatitis; tissue inflammation and liver cell damage is underway.

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