Drinking Patterns and Alcoholic Liver Disease

by National Institute of Health

(Page 2 of 4)

Many studies show that the amount of alcohol consumed and the duration of that consumption are closely associated with cirrhosis.1 (1 In examining trends in alcoholic liver disease, some authors have considered only those cases directly attributable to alcohol [e.g., Douds et al. 2003]. Other authors have determined that many cirrhosis deaths coded as not involving alcohol are in fact alcohol related [particularly for some age groups, including the middle-aged]; thus, these authors have examined total cirrhosis deaths when evaluating trends. One of the best demonstrations of this association was presented by Lelbach, who studied 319 patients in an alcoholism clinic in Germany. He calculated the average amount of alcohol consumed per hour in a 24-hour day. As shown in table 1, patients with normal liver function consumed far less alcohol than did those with cirrhosis. Those who did not have cirrhosis but did have other liver malfunctions had intermediate rates of alcohol intake. In addition, patients with normal liver function had been drinking heavily for only about 8 years on average, whereas those with cirrhosis had been drinking heavily for more than 17 years on average. As this research illustrates, the risk of developing cirrhosis is a function of both quantity and duration of alcohol consumption. Bellentani and Tiribelli recently proposed that cirrhosis does not develop below a lifetime alcohol ingestion of 100 kg of undiluted alcohol. This amount corresponds to an average daily intake of 30 grams of alcohol (between two and three drinks) for 10 years. These investigators also noted that consuming alcohol with food resulted in somewhat lower levels of risk than consuming alcohol by itself.

Cirrhosis Morbidity and Mortality and Average Alcohol Consumption

The strong link between heavy or excessive alcohol use and the development of liver disease took on added significance in the middle of the 20th century, when several researchers began exploring cirrhosis as a potential marker for levels of alcohol problems in populations. Of particular importance was the discovery of a relationship between cirrhosis mortality rates and per capita levels of alcohol consumption in the population. This relationship has proved to be remarkably strong and has been consistently observed across time periods and in various regions of the world. European researchers have observed a lagged relationship between cirrhosis mortality and consumption measures, with the rate of cirrhosis mortality in a year being influenced by the alcohol consumption rates of several previous years. To account for this effect, Skog developed a "distributed lag model," in which the effects of alcohol consumption in a year are distributed over the next several years. Using this model, he was able to explain an apparent inverse relationship between consumption and cirrhosis mortality rates in Great Britain between 1931 and 1958. Incorporating the distributed lag model into the data produced the expected positive relationship between consumption and cirrhosis mortality.

Trends in Cirrhosis Mortality Rates

Liver cirrhosis is a major cause of death in the United States. In 2000, it was the 12th leading cause of death, accounting for 1.1 percent of all deaths, with an age-adjusted death rate3 of 9.6 per 100,000 population. (3 Age adjustment is a statistical method of adjusting for age differences, between populations or over time, that might otherwise distort mortality trends. In the case of chronic diseases, including cirrhosis of the liver, unadjusted mortality rates may appear to be higher for older populations than for younger populations because mortality rates are higher, on average, in older people.) Cirrhosis mortality rates vary substantially among age groups: They are very low among the young but increase considerably in middle age, reaching a peak of 31.1 per 100,000 among people ages 75 to 84. Because of the increase in cirrhosis mortality rates in middle age, the contribution of cirrhosis to total deaths reaches a peak in the 45-54 age group, for which it is the fourth leading cause of death. In relation to the cirrhosis mortality rate in other countries, the United States is in the middle range, as are countries such as Belgium and Canada. Higher rates are seen in countries where people traditionally consume more alcohol than in the United States, such as Spain, France, and Italy. In countries where alcohol consumption is traditionally lower - Iceland, New Zealand, and Norway, for example - cirrhosis death rates are lower.

Cirrhosis mortality rates in the United States have changed substantially over time. Early in the 20th century, these rates were at their highest point. As shown in figure 2, overall cirrhosis mortality rates declined precipitously with the introduction of Prohibition. When Prohibition ended, alcohol consumption and cirrhosis mortality rates increased until the late 1960s and early 1970s, when these rates began to approach levels seen in the first decade of the century. However, in the mid-1970s cirrhosis mortality rates began to decline as they had with the introduction of Prohibition; cirrhosis was the 8th leading cause of death in 1977 but the 12th leading cause of death by 2000. Similar declines in cirrhosis mortality rates have been observed in many developed countries, but in other developed countries cirrhosis death rates have increased. The reasons for the dramatic reductions remain a source of considerable interest, as will be discussed below.

Cirrhosis mortality rates may continue to decline if alcohol consumption rates remain low or fall further. However, the increase in cases of hepatitis C infection in the United States, which are predicted to peak by 2015, may affect the rate of cirrhosis deaths. Because people infected with hepatitis C are more likely to develop cirrhosis when they drink, death rates from cirrhosis may increase in the future, even if drinking levels decline.

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.