Cirrhosis Death Rates, Part 2

by National Institute of Health

(Page 4 of 4)

Other Factors Associated With Increased Rates of Cirrhosis Morbidity and Mortality

Gender Differences

As discussed above, historically the epidemiology of cirrhosis has been linked closely to types and patterns of alcohol consumption. Other factors also may be at work in the development of liver disease. For example, there are important and long-standing gender differences in cirrhosis mortality risk and mortality rates. As shown in figure 2, cirrhosis mortality rates are about two times higher in men than in women. These rates reflect the fact that men typically drink more than women, and that the proportion of heavy drinkers and alcoholics is much higher among men. However, as noted previously, it also appears that at any given level of alcohol consumption, women have a higher likelihood of developing cirrhosis than men. This phenomenon is poorly understood, but several possible explanations have been offered. One is that levels of alcohol dehydrogenase, an enzyme involved in breaking down alcohol, may be lower in the stomachs of females than in males, which would result in a higher blood alcohol content for females than for males who consume equivalent amounts of alcohol. Because damage to the liver is a function of blood alcohol levels and exposure time, factors that lead to higher blood alcohol concentrations could at least partially explain females' higher risk for alcohol-related cirrhosis. Another possible explanation is that estrogen may increase the susceptibility of the liver to alcohol-related damage. Behavioral factors, including drinking patterns and diet, also may contribute to females' higher cirrhosis risk.

Genetic factors, including those that influence alcohol metabolism and risk for alcoholism, also may be involved in the increased risk for cirrhosis seen in women, but there still is considerable debate on this issue, and further research is needed on the nature and the extent of such genetic contributions.

In a recent study, Corrao and colleagues found that 98.1 percent of cirrhosis cases in men but only 67.0 percent of cases in women could be attributed to alcohol consumption, hepatitis C, and hepatitis B. The risk factors for cirrhosis appear to be more complex for women than they are for men, and more research will be required to identify and understand them.

Ethnic Differences

Important differences in cirrhosis rates and cirrhosis mortality also exist among ethnic groups. Although ethnic group differences have been declining in recent years, cirrhosis rates remain higher for Blacks than for Whites in the United States and the highest cirrhosis mortality rates currently are observed among Hispanic groups. Although these differences in cirrhosis rates among Blacks, Whites, and Hispanics seem to suggest higher alcohol consumption levels among Hispanics and Blacks than among Whites, studies of alcohol consumption patterns in these groups tend not to support this interpretation. For example, in recent years, alcohol consumption among Blacks has been less than or comparable with that of Whites.

Several reasons for ethnic group differences in cirrhosis rates have been proposed, including demographic factors related to gender, age, income, education, and employment; biological factors, such as family history of drinking problems; and environmental factors, such as stress. Other suggested factors are differential access to alcoholism treatment services, although as yet no data are available to support this explanation; and differing rates of hepatitis C infection, which appears to be more prevalent among Hispanics than in Black and White populations. Ethnic group differences in cirrhosis risk and mortality may be linked to the possibility that, over time, general health status has improved more for some ethnic groups than others. However, as summarized in table 3, two general health indicators - age-adjusted death rate and life expectancy at birth - showed comparable gains for Blacks and Whites between 1970 and 2000. Thus, it is not yet possible to attribute changes in cirrhosis rates to changes in general health indicators of various groups.

As this discussion indicates, cirrhosis rates in subpopulations, such as those based on gender or ethnicity, can show significant deviations from the rates of cirrhosis that would be expected from alcohol consumption levels alone. These differences, which are not yet well understood, have important implications for research and prevention initiatives. From a public health perspective, an understanding of subpopulation dynamics is critical to the development of programs for preventing alcoholic liver disease.

Conclusion

Alcoholic liver disease is a major source of alcohol-related morbidity and mortality. Heavy drinkers and alcoholics may progress from fatty liver to alcoholic hepatitis to cirrhosis, and it is estimated that 10 percent to 15 percent of alcoholics will develop cirrhosis. The likelihood of developing ALD is, to a large extent, a function of both the duration and amount of heavy drinking, and the per capita consumption of alcohol within populations has been shown to be a strong determinant of cirrhosis mortality rates. Recent studies also suggest that alcohol and hepatitis C may exert a multiplicative effect on risk for cirrhosis and other liver disease.

Although ALD remains a major cause of death, important declines in ALD death rates have been observed in recent years. Undoubtedly these declines were caused in part by changes in alcohol consumption rates, but because the mortality rate decline began when consumption was still increasing, other factors appear to be involved as well. To date, the evidence indicates that increases in participation in AA and other treatment for alcohol abuse have played an important role in reducing cirrhosis mortality rates. Other research has suggested that cirrhosis mortality rates may be more closely related to consumption of certain alcoholic beverages - specifically spirits - than to total alcohol consumption, and that beverage-specific effects can account for the fact that cirrhosis rates appeared to decrease although consumption rates were increasing in the 1970s. Important differences in ALD rates in men and women and among different ethnic groups have been found as well.

Further research into these differences is likely to lead to improved prevention and treatment of alcohol-related liver disease.

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.