Steatotic (Fatty) Liver Disease
- There have been recent changes to the medical terminology covering “fatty” type liver disease to reduce stigma. The term “fatty liver disease” (FLD) has been replaced by “steatotic liver disease” (SLD). SLD is an umbrella term covering “nonalcoholic fatty liver disease” (NAFLD)/”metabolic dysfunction-associated steatotic liver disease” (new term; MASLD); nonalcoholic steatohepatitis (NASH)/metabolic-associated steatohepatitis (new term; MASH); as well as alcohol-related liver disease (ARLD)/ alcohol-associated liver disease (new term; ALD), and the new category, Met+ALD (metabolic with alcohol-associated liver disease), a continuum which can have elements of MASLD and/or ALD.
- Steatotic liver disease (SLD) as a disease category includes several conditions. “Steatosis” is a medical term that describes fat buildup in an organ (usually the liver). A normal liver contains a small amount of fat. When fat buildup goes over 5%-10% in the liver it becomes a health problem.
- SLD classifications are as follows:
- Metabolic dysfunction-associated steatotic liver disease (MASLD); steatosis isn’t associated with excess alcohol consumption but at least one cardiometabolic factor that poses risks to heart health. Cardiometabolic risks include type 2 diabetes mellitus (T2DM), hypertension, overweight (BMI > 25) or obesity (BMI >=30), and dyslipidemia (low HDL and/or high triglyceides).
- Metabolic-associated steatohepatitis (MASH), a serious form of MASLD where fat buildup progresses to inflammation, then tissue damage and scarring (fibrosis)/cirrhosis.
- Alcohol-related liver disease (ARLD)/ alcohol-associated liver disease (new term; ALD); occurring because of excessive alcohol consumption. Excess alcohol use is defined as at least 3 drinks/day (21 per week) in men and 2 drinks/day (14 per week) in women.
- MASLD and increased alcohol intake (Met+ALD); both metabolic risk factors and excess alcohol consumption play a role in liver fat. Which contributes most to the fat buildup varies from person to person.
- Other forms of SLD: For example, various medications and diseases. Sometimes, a specific cause can’t be identified, and this is called “cryptogenic SLD.”
- The majority of people with MASLD have steatotic liver disease (SLD).
Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly nonalcoholic fatty liver disease (NAFLD)
- There have been recent changes to the medical terminology covering “fatty” type liver disease to reduce stigma. The term “fatty liver disease” (FLD) has been replaced by “steatotic liver disease” (SLD). SLD is an umbrella term covering “nonalcoholic fatty liver disease” (NAFLD)/”metabolic dysfunction-associated steatotic liver disease” (new term; MASLD); nonalcoholic steatohepatitis (NASH)/metabolic-associated steatohepatitis (new term; MASH); as well as alcohol-related liver disease (ARLD)/ alcohol-associated liver disease(new term; ALD), and the new category, Met+ALD (metabolic with alcohol-associated liver disease), a continuum which can have elements of MASLD and/or ALD.
- Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the most common causes of liver disease.
- Metabolic dysfunction-associated steatotic liver disease (MASLD) happens when excess fat builds up in the liver. It is a “silent” disease with few or no symptoms. Causes are still being studied, but research points to genetics, digestive disorders, and diet.
- It is not caused by heavy alcohol use (alcohol-associated liver disease or ALD). Causes include diet and nutritional causes, genetics, being overweight/obesity, type 2 diabetes/ insulin resistance, high blood fat/triglyceride levels. One or more traits of metabolic syndrome (traits and medical conditions linked to overweight/obesity), and others.
- Risk factors include family history, older age, growth hormone deficiency, high cholesterol/triglycerides, type 2 diabetes/insulin resistance, metabolic syndrome, obesity, polycystic ovary syndrome, sleep apnea, hypothyroidism, hypopituitarism.
- Some get MASLD even without risk factors.
- Further information on risk factors:
- Anyone, of all ages and races, can have MASLD. It’s more common in Hispanic/Latino people, less common in African American/Black people.
- Middle age, weight and diabetes are associated with MASLD.
- MASLD is present in up to 75% of people with obesity or diabetes and up to 90% of people with advanced or class III obesity.
- MASLD is also caused by other factors experts are still trying to understand.
- The majority of people with MASLD have steatotic liver disease (SLD).
- 50% of patients with obesity have MASLD.
- 50%+ of type 2 diabetes patients have MASLD.
- Metabolic dysfunction-associated steatohepatitis (MASH) is a more advanced form of MASLD in which you have inflammation of the liver and liver damage, in addition to fat in your liver. (See next section.) It is difficult to tell MASLD from MASH; clinical evaluation and testing are needed.
- Weight loss can cause the more severe MASH to change to MASLD, and regaining weight may cause MASLD to switch to MASH.
- MASLD is one of the most common causes of liver disease. About 24% of U.S. adults are estimated to have it. An estimated 80-100 million people in the U.S. have MASLD.
- Globally, MASLD is the most common liver disease, affecting about 25% to about a third of the world’s population.
- Worldwide prevalence of MASLD is increasing at an alarming rate.
- The highest prevalence of MASLD is in Latin America at 44.37%.
- One study (2020) states that worldwide cases of MASLD increased from 391.2 million in 1990 to 882.1 million in 2017.
- Global MASLD/SLD burdens parallel the increase in world obesity rates.
- The estimated global prevalence of MASLD among adults is higher among males than females. However, females’ risk increases as they age.
- Hispanic/Latino people face a higher risk of developing MASLD than other racial or ethnic groups. And African American/Black people with MASLD or MASH are more likely to progress to liver cirrhosis.
- Study results of MASLD prevalence broken down by race/ethnicity vary but strongly indicate trends. Prevalence appears higher among Hispanics, then non-Hispanic Whites and Asians, and lastly, African Americans.
- The prevalence of MASLD/MASH in the U.S. by race/ethnicity ranges as follows: Hispanic (37.0% to 21.2%); non-Hispanic Black population (24.7%-11.6%); non-Hispanic White population (29.3%-12.5%).
- Hispanic/Latino people face a higher risk of developing MASLD than other racial or ethnic groups, according to findings presented at the 2021 AASLD Liver Meeting.
- Black people who develop MASLD or its more severe form, MASH, are more likely to progress to liver cirrhosis, also according to findings presented at the 2021 AASLD Liver Meeting.
- MASLD prevalence in the US has been projected to increase by 21%, from 83.1 million in 2015 to 100.9 million in 2030.
- Food insecurity may be linked to MASLD.
- On April 25, 2024, it was announced that the first national study to assess the prevalence of MASLD will be conducted by Federal Government.
- People typically don’t experience symptoms until MASLD progresses to MASH. It is hard to tell MASLD from MASH without clinical evaluation and testing.
Metabolic dysfunction-associated steatohepatitis (MASH), formerly nonalcoholic steatohepatitis (NASH)
There have been recent changes to the medical terminology covering “fatty” type liver disease to reduce stigma. The term “fatty liver disease” (FLD) has been replaced by “steatotic liver disease” (SLD). SLD is an umbrella term covering “nonalcoholic fatty liver disease” (NAFLD)/”metabolic dysfunction-associated steatotic liver disease” (new term; MASLD); nonalcoholic steatohepatitis (NASH)/metabolic-associated steatohepatitis (new term; MASH); as well as alcohol-related liver disease (ARLD)/ alcohol-associated liver disease(new term; ALD), and the new category, Met+ALD (metabolic with alcohol-associated liver disease), a continuum which can have elements of MASLD and/or ALD.
- MASH is a dangerous and progressive form of MASLD in which patients have liver inflammation and damage, as well as excess fat.
- Estimates of MASH vary but fall within similar ranges: One study of 2017-2020 NHANES data estimated the prevalence of MASH among US adults in the range of 1.3% to 4.8% (2017–March 2020 National Health and Nutrition Examination Survey (NHANES) data). Another analysis (2016) estimated 1.5% to 6.5% of U.S. adults as having MASH. J. Hopkins Medicine estimates about 2% to 5% have MASH.
- Approximately 24% of U.S. adults have MASLD/MASH, and about 1.5% to 6.5% adults have MASH.
- MASH annual incidence rate increased from 1.51% in 2010 to 2.79% in 2020.
- From 2016 to 2020, >1.8 million patients in the US were diagnosed with MASH annually.
- MASH is the number one cause for liver transplants in women and those 65+ in the US.
- MASH is projected to become the leading reason for liver transplantation in all population categories.
- MASH progression can result in cardiovascular disease; hepatocellular carcinoma (liver cancer); and liver-related/all-cause mortality. MASH progression is often slow, but some may have rapid progression from no fibrosis (development of fibrous tissue in the liver, similar to scarring) to advanced fibrosis in about 6 years.
- MASH is difficult to identify until the late stages of the disease.
- MASH Is the second most common and the most rapidly Increasing indication for liver transplantation in the US.
- In the U.S., MASLD affects between 80 and 100 million people, about 20-25% of them will progress to MASH. Many do not know they have the disease. 11% of MASH patients will develop cirrhosis/liver failure.
- MASH prevalence is projected to increase 63% between 2015 and 2030. One model estimates that by 2030, the number of MASH patients with advanced fibrosis (scarring) will double, resulting in 800,000 liver-related deaths.
- Between 2015 and 2030, the prevalence of MASH is anticipated to increase by 63%. By 2030, modeling data estimates the number of patients with MASH-related advanced fibrosis (scarring) is expected to double, which will result in 800,000 liver-related deaths.
- The high rate of obesity in the US drives the burden of MASH.
- 47% of MASH patients have diabetes mellitus (DM).
- Breakdown of MASH prevalence by race/ethnicity/gender (2022 study of NHANES data for 5492 patients):
- Overall prevalence of MASH was 7.6%.
- Mexican Americans had the highest prevalence (10.6%), followed by other Hispanics (9.1%).
- Non-Hispanic Whites had the lowest prevalence (6.8%).
- Females had lower prevalence (4.8%) than males (10.4%).
- Among males, Mexican Americans had the highest prevalence (14.3%), followed by African American/Blacks (11.3%)
- “Other race” category had the lowest prevalence (7.7%).
- Among males and females, there was no association between MASH and race/ethnicity.
- The highest prevalence of MASH was among Mexican American males.
- African American/Black people who develop MASLD or its more severe form, MASH, are more likely to progress to liver cirrhosis, according to findings presented at the 2021 AASLD Liver Meeting.
- Among patients with MASLD, risk of MASH was higher in Hispanic/Latino people and lower in African American/Black people than White people.
- MASH was the second leading cause of liver transplant on waiting lists in the US (after alcohol-associated liver disease or ALD - 2022 data) and is projected to become the leading cause.
- In 2016, MASH emerged as the primary cause of liver transplantation in the US among people born 1945-1965. And a recent study found that MASH has become the primary cause of transplants in the over-65 population (2018-2020).
- MASH is the leading cause of liver transplant in women.
- MASH may progress to hepatocellular cancer (HCC), the third leading cause of cancer-related death globally and also a leading cause of liver transplant. MASH was also determined to be both the leading and fastest-rising cause of HCC in liver transplant candidates.
- The 20% Rule of MASH Progression: Approximately 20% of patients with MASH will progress to cirrhosis or develop decompensation, over a 2-year period.
- High-risk, or at-risk, MASH is defined as: Patients with MASH who have both substantial liver fibrosis (F2 or greater) and a MASLD activity score (MAS) of 4 or greater. It is imperative for clinicians to medically intervene with these patients. MAS can range from 0 to 8 and is calculated by the sum of scores of steatosis (0-3), lobular inflammation (0-3) and hepatocyte ballooning (0-2). In patients with MASLD, MAS score of ≥ 5 strongly correlated with a diagnosis of “definite MASH” whereas MAS ≤ 3 correlated with a diagnosis of “not MASH”.
- Though the global burden of MASH is on the rise, there is no single strategy to address this serious health crisis.
How MASLD/NAFLD Affects Children
- One study of 408 children with obesity (mean age of 13.2 years; 2018), MASLD was present in nearly one-third of boys and one-fourth of girls.
- MASLD is the most common form of pediatric liver disease in the U.S., more than doubling the past 20 years, in part because of increasing childhood obesity. Some Studies estimate 5% to 10% of children have MASLD.
- Pediatric MASLD is often associated with metabolic syndrome.
- A recent story in the Washington Post (10/3/2023) covering the growing crisis of childhood liver disease highlighted the following facts:
- Before the turn of the century, pediatric fatty liver disease was relatively rare. Now millions are affected; the journal Clinical Liver Disease estimates 5% to 10 % of all children in the US have MASLD — about as common as childhood asthma.
- There were large jumps in MASLD incidence across all ages in the US; the steepest increase by far was in children (data 2017-2021).
- The rate of MASLD diagnosis more than doubled in children up to age 17 (insurance claim data analyzed for The Post by Trilliant Health). Some of that increase is because of more vigilant reporting and testing recently. The trend, however, holds true.
- The crisis is acute in the Southeast, where pediatric obesity rates are highest.
- When more than 5% of liver cells contain fat, steatotic liver disease (SLD) is indicated (5-10%). Pediatric specialists are finding children with livers of 30-40% fat, even as high as 60% fat.
- There is a rise in transplants for fatty liver in people in their 20s and 30s.
- The story also highlighted the link between ultra-processed foods and pediatric/childhood obesity/MASLD.
- Studies estimate that 20% to 50% of children with MASLD have the MASH.
- When compared to people who develop MASLD during adulthood, people who develop MASLD during childhood are more likely to have MASH and its complications or liver disease as adults.
- Children with MASH can develop cirrhosis, but the complications of cirrhosis, such as liver failure and liver cancer, usually happen in adulthood.
- MASLD is more common in boys than in girls.
- MASLD occurs in children of all races and ethnicities but is most common in Hispanic/Latino children and Asian American children, followed by White children.
- MASLD is less common in younger children, girls, and African American/Black children.
- One study: Prevalence of MASLD in children broken down by race/ethnicity (2006 data):
- Children of Hispanic/Latino ethnicity (11.8%)
- Asian children (10.2%)
- White children (8.6%)
- Black/African American children (estimate of 1.5%)
Met+ALD (metabolic with alcohol-associated liver disease)
- There is a new category for people with alcohol-associated liver disease (ALD) and MASLD, called Met+ALD (metabolic with alcohol-associated liver disease). It is a continuum which can have elements of MASLD and/or ALD. Met-ALD is the result of fat in the liver from alcohol use combined with MASLD. MetALD can result in liver inflammation, scarring, and cirrhosis.
Last updated on December 11th, 2025 at 01:41 pm