Researchers have argued in a new paper that the lines between non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (AFLD) are blurred and that a reevaluation of the definitions of this family of liver diseases is in order, MedPage Today reports.

Currently, the only official distinction between the two diagnoses is the person in question’s alcohol consumption—specifically, whether an individual’s alcohol intake is over the threshold considered to be significant enough to have driven the progression of liver disease. Currently, that threshold is generally considered 30 grams of alcohol per day for men and 20 daily grams for women. (A standard drink has about 14 grams of alcohol.)

Publishing their thesis in the journal Gastroenterology, investigators note that the diagnostic criteria for NAFLD were first established in 1980 and have never been revisited.

There is conflicting evidence about whether moderate alcohol consumption improves or worsens outcomes of those with NAFLD.

According to the authors of the new paper, there are four main liver categories, or phenotypes, that those in the liver disease clinical community should consider instead of simply relying on NAFLD and AFLD as diagnoses. These definitions, which take into account varying levels of alcohol consumption as well as metabolic abnormalities, include: 

  1. liver disease that is genuinely related to alcohol use;
  2. liver disease that is predominantly characterized by the classic definition of AFLD but is compounded by other metabolic factors;
  3. classic NAFLD, in which the individual consumes virtually no alcohol and the disease progression is driven by metabolic factors;
  4. fatty liver disease that is driven by metabolic abnormalities in an individual with moderate alcohol intake of no more than 30 grams daily.

 Current definitions of NAFLD do not encompass that last category of disease, which is actually probably the most common of the four groups. Additionally, NAFLD criteria do not currently acknowledge systemic metabolic dysfunction in people with the disease.

To read the MedPage Today article, click here.

To read the study, click here.