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Page 2 of 17 Gulati et al. Metab Target Organ Damage 2024;4:9 https://dx.doi.org/10.20517/mtod.2023.45

contributors.

MASLD describes the abnormal accumulation of fat in the liver in the presence of at least one of five
2
cardiometabolic risk factors: (1) body mass index (BMI) ≥ 23 kg/m or waist circumference ≥ 90 cm for male
and ≥ 85 cm for female; (2) fasting serum glucose ≥ 100 mg/dL or type 2 diabetes or treatment for type 2
diabetes; (3) blood pressure ≥ 130/85 mmHg or antihypertensive treatment; (4) triglycerides ≥ 150 mg/dL or
lipid-lowering treatment; or (5) high-density lipoprotein (HDL) cholesterol ≤ 40 mg/dL for male and ≤ 50
mg/dL for female or lipid-lowering treatment . MASLD is an umbrella term for a spectrum of diseases
[1]
ranging from simple steatosis, in which patients do not have significant liver inflammation or damage, to
steatohepatitis (MASH), in which fat accumulation causes oxidative stress leading to inflammation. MASLD
[2]
is the most common cause of chronic liver disease in the developed world . The global prevalence of
MASLD is estimated to be 30 percent, with the highest prevalence in the Middle East and North Africa (26.5
percent each) . The incidence of MASLD is increasing due to the rising incidence of obesity and diabetes
[3]
[4]
mellitus . The NHANES 1999-2018 survey found that the prevalence of MASLD in young adults in the
United States increased from 9.98% in 1999 to 19.49% in 2018 . Based on predictive modeling, MASLD
[5]
[6]
prevalence is likely to increase from 83.1 million cases in 2015 to 110.9 million by 2030 . In the United
States, MASLD-related cirrhosis is currently one of the leading indications for liver transplantation, and
annual medical costs of MASLD in the United States are estimated to be approximately $103 billion
($1612.18 per patient) . In addition, from 2010-2019, the global all-age, age-standardized deaths from liver
[2]
[3]
cancer related to MASLD increased faster than liver cancer deaths related to other etiologies .
Given the staggering prevalence of MASLD, it is important to determine which populations are at greater
risk for the development and progression of MASLD. Unfortunately, effective risk stratification tools do not
yet exist due to the heterogeneity and unpredictability of the natural history of MASLD. However,
disparities by race and ethnicity have been observed. In this review, we aim to describe epidemiologic data
supporting these disparities, and explore several possible contributors. This analysis focuses on newer
evidence when available. We use the term MASLD, a new nomenclature as of June 2023 for non-alcoholic
fatty liver disease (NAFLD) . An important caveat is that previous studies identified patients according to
[1]
the NAFLD definition. There is a significant overlap between NAFLD and MASLD, with both diagnoses
[7,8]
requiring the presence of hepatic steatosis . In MASLD, the presence of at least one cardiometabolic risk
[1]
factor is required for the diagnosis . Implementing this definition, a study investigated 1,333 patients at
Swedish university hospitals with confirmed NAFLD and found that only 4 patients (0.3%) did not meet the
[7]
criteria for a diagnosis of MASLD . Similarly, utilizing proton-magnetic resonance spectroscopy, Song et al.
recently reported a minimal difference in the prevalence of NAFLD (25.6%) and MASLD (26.7%) in 1,106
[9]
random persons from Hong Kong . Studies such as these support the idea that previous data collected on
NAFLD can be extrapolated to MASLD, given the large overlap. However, multi-society guidelines
[1]
recommend the use of the term MASLD .

We use the terms Black, Hispanic, Asian, and White to describe race and ethnicity, as these are commonly
reported in the literature. However, these terms are vague and overlook substantial heterogeneity in
ancestry within groups. Most studies discussing race and ethnicity disparities in MASLD rely on self-
reported data, which is often incomplete or poorly elaborated . Better inclusivity of observational studies
[10]
and clinical trials, as well as granular reporting of race, ethnicity, and sociodemographic factors, will
hopefully lead to a better understanding of disparities in the future.