Nonalcoholic fatty liver disease (NAFLD) is present in around one-third of the US adult urban population, report US researchers who also found that the incidence of the disease varies between ethnic groups.
Aiming to determine the prevalence of NAFLD in the three major ethnic groups living in the USA - Whites, Blacks, and Hispanics - the investigators used proton nuclear magnetic resonance spectrometry (1H-MRS) to measure hepatic triglyceride content (HTGC) in 2287 adults living in Dallas, Texas.
They found that almost one-third of the people studied had hepatic steatosis, defined as an HTGC greater than 5.5% of the liver, and, as expected, the incidence of hepatic steatosis varied significantly with ethnicity.
Specifically, the frequency of steatosis was significantly higher in Hispanics than in Whites, while Black individuals had the lowest incidence of the disease, with rates of 45%, 33%, and 24%, respectively.
Furthermore, while the prevalence of hepatic steatosis was similar in both sexes among Black and Hispanic individuals, almost twice as many White men than women had the disease, at 42% and 24%, respectively.
Of note, 79% of individuals with hepatic steatosis had normal serum alanine aminotransferase (ALT) levels, a finding the researchers say "provides further evidence that a normal serum ALT level provides little diagnostic or prognostic value when assessing patients for NAFLD."
Analysis indicated that "the higher prevalence of hepatic steatosis in Hispanics was due to the higher prevalence of obesity and insulin resistance in this ethnic group," lead investigator Helen Hobbs (University of Texas Southwestern Medical Center, Dallas) and colleagues write in the journal Hepatology.
"However, the lower frequency of hepatic steatosis in blacks was not explained by ethnic differences in body mass index, insulin resistance, ethanol ingestion, or medication use."
The team concludes: "Understanding the mechanisms responsible for the ethnic differences in the prevalence of hepatic steatosis and steatosis-related liver injury may provide clues to the development of new therapeutic approaches for the prevention and treatment of this disorder."
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