Understanding Alcoholic Liver Disease

by National Institute of Health

This article describes the various forms of alcoholic liver disease, with particular emphasis on cirrhosis, the form of liver disease that often is most associated with alcohol abuse and about which the most information is available. Epidemiological research has evaluated the prevalence of ALD and the factors that often contribute to the disease. Although the most potent factor in ALD is the excessive consumption of alcoholic beverages, gender and ethnic differences also account for some important variations in rates of liver disease. Mortality rates from cirrhosis have declined in the United States and some other countries since the 1970s. A number of factors may have contributed to this decline, including increased participation in treatment for alcohol problems and Alcoholics Anonymous membership, decreases in alcohol consumption, and changes in the consumption of certain types of alcoholic beverages.

One of the most enduring insights into the effects of alcohol has been the assertion that heavy alcohol consumption increases mortality rates, especially those from cirrhosis of the liver and other forms of liver disease. The scientific study of alcohol-related mortality began in the 1920s with Pearl's studies of death rates among various types of drinkers. He and others found that heavy drinkers had higher rates of overall mortality and of mortality from cirrhosis than did lighter drinkers or abstainers. Since then, mortality studies have continued to demonstrate that heavy drinkers and alcoholics die from cirrhosis at a much higher rate than the general population.

Alcohol consumption increased substantially in many countries after World War II, which spurred greater interest in the effects of alcohol consumption on cirrhosis and other forms of alcoholic liver disease. One of the most influential efforts to summarize research in this area was undertaken in 1975 by an international group of scientists sponsored by the World Health Organization. The resulting book, Alcohol Control Policies in Public Health Perspective, reviewed studies of clinical and nonclinical populations of heavy drinkers. All studies found that a greater proportion of heavy drinkers died of cirrhosis than would be expected based on rates of cirrhosis deaths in the general population (i.e., liver cirrhosis deaths among heavy drinkers ranged from 2 to 23 times higher than the rate that would be expected in the general population). This research established a firm connection between heavy alcohol consumption and liver disease. Investigators also have observed that the price of alcohol is a significant determinant of alcohol consumption and thus of cirrhosis mortality rates. These findings have laid the foundation for an influential public health approach to controlling liver disease and other alcohol problems that emphasizes the control of alcohol's availability and includes recommendations to control cirrhosis and other alcohol-related problems through taxation. The validity of this availability-control approach has been widely supported and investigations of the epidemiology of ALD have continued to be central to it.

Types of Alcoholic Liver Disease

The most prevalent types of alcoholic liver disease are fatty liver, alcoholic hepatitis, and cirrhosis. Often, as people continue to drink heavily, they progress from fatty liver to hepatitis to cirrhosis. The disorders can also occur together, however, and liver biopsies can show signs of all three in some people.

Alcoholic Fatty Liver

About 20 percent of alcoholics and heavy drinkers develop fatty liver, or steatosis. In many cases there are no clinical symptoms except for an enlarged liver (hepatomegaly). Fatty liver can be reversed if alcohol consumption is stopped or significantly reduced, but the condition can lead to death if alcohol consumption is not reduced or stopped. Some biopsies from people with fatty liver show inflammatory changes, an early sign of more serious liver disease.

Alcoholic Hepatitis

Alcoholic hepatitis usually is diagnosed when a liver biopsy indicates inflammatory changes, liver degeneration, fibrosis, and other changes to liver cells. Common clinical signs of alcoholic hepatitis include swollen liver, nausea, vomiting, and abdominal pain. Patients also may experience fever, jaundice, liver failure, and bleeding. The rate of mortality in severe cases is about 50 percent. If heavy drinking continues, about 40 percent of cases of alcoholic hepatitis will develop into cirrhosis.

Alcoholic Cirrhosis

Cirrhosis of the liver is the most serious form of ALD and a cause of many deaths and serious illnesses. In cirrhosis, scar tissue replaces normal liver tissue, disrupting blood flow through the liver and preventing it from working properly. Clinical signs of cirrhosis include redness of the palms caused by capillary dilation (palmar erythema); shortening of muscles in the fingers (contractures) caused by toxic effects or fibrous changes; white nails; thickening and widening of the fingers and nails (clubbing); liver enlargement or inflammation; and abnormal accumulation of fat in normal liver cells (fatty infiltration). Diagnosis of cirrhosis must be made with biopsies, although laboratory tests can be helpful as well.

About 10 percent to 15 percent of people with alcoholism develop cirrhosis, but many survive it. Many are unaware that they have it, and about 30 percent to 40 percent of cirrhosis cases are discovered at autopsy. The 5-year survival rate for people with cirrhosis who stop drinking is about 90 percent, compared with 70 percent

of those who do not stop drinking. However, for late-stage cirrhosis - that is, when jaundice, accumulation of fluid in the abdomen, or gastrointestinal bleeding have occurred - the survival rate is only 60 percent for those who stop drinking and 35 percent for those who do not.

Other Forms of Liver Disease Affected by Alcohol

Alcohol can be a factor in other forms of liver disease not specifically attributed to it, and alcohol may interact with risk factors for other forms of liver disease. For example, people with alcohol-related cirrhosis are at much higher risk for the development of liver cancer. Likewise, heavy drinking in combination with hepatitis B or C substantially increases the risk of liver cirrhosis, compared with the risk associated with heavy drinking alone.

About the Author

NIH is the nation's medical research agency - making important medical discoveries that improve health and save lives. The National Institutes of Health (NIH), a part of the U.S. Department of Health and Human Services, is the primary Federal agency for conducting and supporting medical research.