Alcoholic liver disease (ALD) refers to a broad spectrum of liver injuries, including alcoholic fatty liver, alcoholic hepatitis, and alcoholic cirrhosis. ALD is among the most common liver diseases in the United States; however, it varies significantly by ethnicity. A new study examining the role of ethnicity in determining the age of onset and severity of ALD, and comparing risk factors for its progression among ethnic groups, has found that ethnicity is a major factor affecting the age and severity of different subtypes of ALD.
Results will be published in the March 2015 online-only issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"Alcoholic liver disease is a spectrum of conditions that range from hepatic steatosis, which is fat deposition in the liver and it is reversible with sobriety, to alcoholic hepatitis which is a more severe condition characterized by extensive and severe inflammation in the liver and often requires hospitalization," explained Valentina Medici, associate professor of internal medicine at UC Davis Health System as well as corresponding author for the study. "The final stage is alcoholic cirrhosis, characterized by fibrosis or deposition of scar tissue in the liver. ALD develops in response to a long duration of high amounts of alcohol, but not all individuals develop ALD."
"ALD is very common," added Christopher L. Bowlus, professor and acting chief of the division of gastroenterology and hepatology at UC Davis Health System, "and affects individuals of all ages, races, and socioeconomic status. It is the most common cause of liver-related death, accounting for over 15,000 deaths every year. However, not everyone is affected by alcohol the same way. Even if the same amount of alcohol is consumed, the liver damage from alcohol in some people can be more severe than in others, suggesting that other factors, such as genes and environment, can influence the development of liver damage."
Medici and her colleagues conducted a retrospective chart review of all patients with ALD who were admitted or were followed as outpatients at UC Davis Medical Center between 2002 and 2010. After excluding hepatitis-B infected and HIV-positive subjects, researchers reviewed the charts of 791 ALD patients, including 130 with alcoholic fatty liver, 154 with alcoholic hepatitis, and 507 with alcoholic cirrhosis.
"For the first time, we showed that Hispanics present at a four to 10 years younger age than Caucasians and African/Americans, and that ethnicity could predict the age of presentation of alcoholic fatty liver and alcoholic hepatitis," said Medici. "In addition, alcoholic Hispanics tend to be more frequently obese and diabetic than the other ethnicities. Also, Hispanics with alcoholic cirrhosis were more likely to be hospitalized than Caucasians, indicative of a possibly more severe disease."
"The development of ALD in Hispanics several years younger than whites ... did not appear to be due to other possible factors such as chronic viral hepatitis C, diabetes or obesity, all of which are can cause liver damage," said Bowlus. "Genetic and environmental factors may play an important role as they can accelerate the onset and progression of ALD. There might also be differences in the pattern of drinking and type of alcohol consumed."
"The data in our paper showed that Hispanics with all stages of liver disease had greater body mass index in the obesity range and that those with alcoholic cirrhosis had increased incidence of type II diabetes and the metabolic syndrome," said Medici. "The co-existence of insulin resistance and metabolic syndrome that occurs with increased BMI is known to contribute to liver injury independent of alcohol use in the condition known as non-alcoholic fatty liver disease (NAFLD). Others have shown that the presence of diet-induced NAFLD contributes to the incidence and severity of co-existent alcoholic liver disease in alcohol consumers. However, it is important to notice that, when excluding subjects with obesity and diabetes from the analysis, Hispanics with ALD were still younger than Whites/Caucasians. Therefore, Hispanics have most likely many risk factors that contribute to the development of their liver disease."
"The findings in this study are important for two reasons," said Bowlus. "First, they demonstrate the difference ethnicity has on the clinical manifestation of ALD. Second, they lay the ground work for future clinical and laboratory studies to understand the interactions between alcohol, genes, and the environment."
"Hispanics may find it important to know that heavy drinkers can develop ALD at a younger age, that obesity contributes to this risk, and that preventive steps should be taken if their relatives or friends engage in risky drinking behavior," said Medici. "In addition, primary-care physicians in the community will want to screen regularly for the presence and extent of alcohol drinking, as well as the potential contributing factors of obesity and ethnicity as high risk factors for the development of alcoholic liver disease in their high alcohol-consuming patients."
"No one should feel that they are free from ALD," added Bowlus. "If you drink beyond a moderate amount, there is a risk you will develop serious ALD. If you are Hispanic, you should be particularly concerned because you may be at even greater risk of serious liver damage from alcohol."
Alcoholism: Clinical & Experimental Research (ACER) is the official journal of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism. Co-authors of the ACER paper, "Ethnic Differences in Presentation and Severity of Alcoholic Liver Disease," were: Robert Levy, Andreea M. Catana, and Charles H. Halsted of the department of internal medicine, and the division of gastroenterology and hepatology at UC Davis; and Blythe Durbin-Johnson of the department of public health sciences in the division of biostatistics at UC Davis. The study was funded by the National Center for Advancing Translational Sciences, the National Institutes of Health, and the Division of Gastroenterology and Hepatology at UC Davis.