What is Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)? Causes and Symptoms
Written by: CDHF
Updated: February 5th, 2026
In 2023, experts in liver disease came to a decision to rename non-alcoholic fatty liver disease (NALFD) to metabolic dysfunction-associated steatotic liver disease (MASLD).1 MASLD is the most common cause of liver disease in North America and is soon to become to leading cause for liver transplantation. For the purpose of this article, we will be referring to this condition as MASLD.
What is MASLD?
Metabolic dysfunction-associated steatotic liver disease (MASLD) is a medical condition characterized by the accumulation of fat in the liver of individuals who consume little to no alcohol or do not have a history of excessive alcohol consumption. It is one of the most common liver disorders in the world and is often associated with obesity, insulin resistance, and metabolic syndrome. MASLD exists on a spectrum that encompasses simple fat deposition in the liver, liver plus fat inflammation and/or scarring or cell damage, and ultimately liver cirrhosis in its most advanced form.
Causes and Risk Factors
MASLD is primarily driven by lifestyle factors and metabolic conditions. Some of the key causes and contributing factors to MASLD include:
- Obesity: Obesity is one of the primary risk factors for MASLD. In Canada, as in many other developed nations, rates of obesity have been on the rise among both adults and children. Excess body fat, particularly abdominal obesity, is closely linked to the development of MASLD. In fact, according to the Canadian Liver Foundation, almost 30% of Canadians 18 and older (roughly 7.3 million adults) reported height and weight that classified them as either overweight or obese in 2018.
- Insulin Resistance: Insulin resistance is a metabolic condition in which the body’s cells do not respond effectively to insulin. It is a key factor in the development of MASLD. Canada has seen an increase in insulin resistance and type 2 diabetes, which are often associated with MASLD.
- Unhealthy Diet: Consumption of diets high in sugar, saturated fats, and processed foods is common in Canada. These dietary patterns contribute to obesity, insulin resistance, and the accumulation of fat in the liver.
- Physical Inactivity: Sedentary lifestyles and a lack of regular physical activity are prevalent in Canada.3 Physical inactivity can exacerbate obesity and insulin resistance, both of which contribute to MASLD.
- Genetic Factors: While lifestyle factors play a significant role in MASLD, genetics can also contribute to an individual’s risk. Some people may be genetically predisposed to developing MASLD.
- Other Metabolic Conditions: Metabolic syndrome, characterized by a combination of factors such as obesity, high blood pressure, high blood sugar, and abnormal lipid levels, increases the risk of MASLD.
- Age and Gender: MASLD can affect individuals of all ages, including children, but its prevalence increases with age. Additionally, it tends to be more common in males than females.
- Ethnicity: Certain ethnic groups may have a higher predisposition to MASLD. In Canada, this is particularly relevant in populations with a higher prevalence of obesity and metabolic syndrome.
- Medications and Medical Conditions: Some medications and medical conditions can contribute to the development of MASLD. For example, certain drugs, such as corticosteroids and tamoxifen, can increase the risk.
- Environmental Factors: Environmental factors, such as exposure to toxins or pollutants, can potentially contribute to liver damage in some cases, although these factors are less common causes of MASLD compared to lifestyle-related factors.
Symptoms
MASLD is often considered a “silent” liver disease because many individuals with MASLD do not experience noticeable symptoms, especially in the early stages of the condition. Symptoms tend to become more evident as MASLD progresses to more advanced stages or develops into metabolic dysfunction-associated steatohepatitis (MASH), which is characterized by liver inflammation and damage. Common symptoms and signs of MASLD and MASH include:
- Fatigue: People with MASLD or MASH may often feel unusually tired or fatigued, even after getting adequate sleep.
- Right Upper Abdominal Discomfort: Some individuals may experience discomfort or a dull ache in the upper right side of the abdomen, where the liver is located. This discomfort is typically mild and may come and go.
- Unexplained Weight Loss or Poor Appetite: In more advanced cases of MASLD or MASH individuals may unintentionally lose weight or have a decreased appetite.
If cirrhosis, (the most advanced stage) occurs, more pronounced symptoms may manifest, including jaundice characterized by yellowing of the skin and the whites of the eyes, itchy skin, and swelling in the legs, ankles, feet, or abdomen (edema).
As MASLD is often asymptomatic in its early stages, it is often discovered incidentally during medical tests or check-ups. Routine screening for MASLD is not typically performed unless risk factors are present, such as obesity, diabetes, or abnormal liver function test results. If you suspect you may have MASLD or are experiencing concerning symptoms related to your liver or overall health, it is essential to seek medical evaluation and guidance from a healthcare provider.
Early detection and management can help prevent the progression of MASLD to more severe liver conditions. Once MASLD is suspected, determining the severity of the disease is an important next step. This can be achieved through bloodwork and scoring systems and/or specialized imaging such as an ultrasound or MRI, which we talk about in this article. This helps determine the level of fibrosis or scarring. If diagnosed with advanced fibrosis, referral to a liver specialist or hepatologist is recommended.
This article was made possible due to an unrestricted educational grant from Novo Nordisk.
References
- Rinella, Mary E.1; Lazarus, Jeffrey V.2,3; Ratziu, Vlad4; Francque, Sven M.5,6; Sanyal, Arun J.7; Kanwal, Fasiha8,9; Romero, Diana2; Abdelmalek, Manal F.10; Anstee, Quentin M.11,12; Arab, Juan Pablo13,14,15; Arrese, Marco15,16; Bataller, Ramon17; Beuers, Ulrich18; Boursier, Jerome19; Bugianesi, Elisabetta20; Byrne, Christopher D.21,22; Castro Narro, Graciela E.16,23,24; Chowdhury, Abhijit25,26; Cortez-Pinto, Helena27; Cryer, Donna R.28; Cusi, Kenneth29; El-Kassas, Mohamed30; Klein, Samuel31; Eskridge, Wayne32; Fan, Jiangao33; Gawrieh, Samer34; Guy, Cynthia D.35; Harrison, Stephen A.36; Kim, Seung Up37; Koot, Bart G.38; Korenjak, Marko39; Kowdley, Kris V.40; Lacaille, Florence41; Loomba, Rohit42; Mitchell-Thain, Robert43; Morgan, Timothy R.44,45; Powell, Elisabeth E.46,47,48; Roden, Michael49,50,51; Romero-Gómez, Manuel52; Silva, Marcelo53; Singh, Shivaram Prasad54; Sookoian, Silvia C.15,55,56; Spearman, C. Wendy57; Tiniakos, Dina11,58; Valenti, Luca59,60; Vos, Miriam B.61; Wong, Vincent Wai-Sun62; Xanthakos, Stavra63; Yilmaz, Yusuf64; Younossi, Zobair65,66,67; Hobbs, Ansley2; Villota-Rivas, Marcela68; Newsome, Philip N69,70; on behalf of the NAFLD Nomenclature consensus group. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. Hepatology ():10.1097/HEP.0000000000000520, June 24, 2023. | DOI: 10.1097/HEP.0000000000000520
- Canadian Liver Foundation https://www.liver.ca/patients-caregivers/liver-diseases/fatty-liver-disease/
- Prince SA, Melvin A, Roberts KC, et al. Sedentary behaviour surveillance in Canada: trends, challenges and lessons learned. International Journal of Behavioral Nutrition and Physical Activity. 2020; 17: 34.
