Epidemiology and Comorbidity - Alcohol Use Disorders

Epidemiology and Comorbidity

Patterns of Drinking and Types of Alcohol Problems in the USA

The majority (85.8%) of the US population aged 18 year and older has used alcohol in their lifetime, although only half (50.0%) report current drinking. The highest rates of current use are among young adults aged 18 to 25 years, with males predominat-ing. NonHispanic whites have the highest prevalence of drink-ing (89.3% lifetime use and 53.7% past month use), while Asians are least likely to drink (62.7% lifetime and 33.4% current). The prevalence of drinking is positively associated with education level; persons with less than a high school education are almost half as likely to report past month drinking as college graduates (33.5% compared with 62.6%).

More than 1 in 5 persons aged 18 years and older (21.4%) reported binge drinking in the past month, and more than 1 in 20 (6.1%) reported heavy alcohol use. Consistent with the prevalence of drinking, both binge and heavy drinking are more likely to be found among young adults and males. Compared with women, men are twice as likely to binge drink (defined as five or more drinks per occasion) and are four times more likely to be heavy drinkers. Asians, followed by blacks, have the lowest levels of binge drinking (11.6 and 18%, respectively); Hispanics and those reporting a mixed racial background have the highest prevalence of binge drinking (23.5 and 23.1% respectively). Heavy drinking is most often reported by those with multiple racial backgrounds (8.9%), followed by nonHispanic whites (6.5%). In contrast to the demographic correlates of any alcohol use, binge drinking and heavy alcohol use appear to have a curvilinear relationship with education level. The lowest levels of binge and heavy prob-lem drinking are found among those with the least and most education.

Several large-scale community studies conducted since 1980 have provided estimates of the lifetime and past year preva-lence of alcohol use disorders in the general population. For ex-ample, the National Comorbidity Study (NCS), a representative household survey of 8098 persons aged 15 to 54 years that was conducted between 1990 and 1992, assessed lifetime and past-year alcohol disorders using DSM-III-R criteria. The NCS esti-mated that the lifetime prevalence of alcohol abuse and alcohol dependence for adults 18 to 54 years old were 9.4 and 14.1%, re-spectively, indicating that more than one-in-five young to mid-dle-aged adults in the USA have had a pattern of alcohol use that met criteria for lifetime alcohol disorder. The prevalences of al-cohol abuse and dependence during the 12 months preceding the interview were 2.5 and 4.4%, respectively.

Narrow and colleagues (2002) applied “clinically signif-icant” criteria to the NCS data to determine the percentage of the population who were in need of treatment, more in keeping with DSM-IV diagnostic guidelines. The revised estimates of the 12-month prevalence of clinically significant alcohol disorder is 5.2% for adults in the USA (including 6.5% of adults aged 18–54 years and 2% of adults aged 55 years or older).

Differences in the rates of disorder across the various stud-ies have been attributed to differences in diagnostic criteria, age ranges of the samples and sampling approaches. Regardless of the differences, it should be noted that all of these studies are based on self-reports of drinking behavior and are likely to be conservative estimates of the prevalence of problem drinking due to underreporting.

Analyses of national prevalence data show that disorder rates vary by gender, age, race, ethnicity, socioeconomic status and geographic location. The prevalence of alcohol disorder is consistently found to be higher among men than women, often at a ratio of two to one or greater Substance Abuse and Men-tal Health Services Administration, 2000). Evidence suggests, however, that the gender differential has narrowed among morerecent cohorts of young adults, in part due to an increased likeli-hood of early onset drinking among women and the subsequent emergence of drinking problems. The highest prevalence rates of alcohol abuse and dependence occur among young adults, with a gradual decline associated with increasing age. The highest rates of past year dependence were found among those identifying their racial/ethnic background as “multiple race” (9%). There is a negative association between education level and alcohol de-pendence and 1-year alcohol dependence risk is highest among the unemployed). Urban residence is associated with higher rates of alcohol dependence.

Adverse consequences of drinking include a variety of so-cial, legal and medical problems. Overall, alcohol-related mortal-ity in 1988 totaled 107 800 deaths, or about 5% of all deaths in the USA, putting it among the top four causes of death. Of alco-hol-related deaths, approximately 17% were directly attributable to alcohol, 38% resulted from diseases indirectly attributable to alcohol and 45% were attributable to alcohol-related traumatic injury (US Department of Health and Human Service, 1994). Al-cohol-related mortality declined during the last few decades of the 20th century.

Alcohol-related morbidity is manifested in virtually all or-gan systems. The primary chronic health hazard associated with heavy drinking is cirrhosis of the liver, which in 1988 was the ninth leading cause of death in the USA. Although the percent-age of drivers in fatal crashes with BALs in excess of the legal limit has declined in recent years, alcohol intoxication remains a major contributor to this and other types of accidental injury, as well as to suicide and homicide. In addition, heavy drinking has been implicated in such health conditions as FAS, esophageal cancer, chronic pancreatitis, nutritional deficiencies, cardiomy-opathy, hypertension and neurological problems. The social con-sequences of alcohol abuse and dependence are equally serious, with heavy drinking contributing to a variety of family, work and legal problems. The economic impact of alcoholism is sub-stantial. Alcohol abuse and dependence contribute to unemploy-ment, reduced productivity in the workplace and crime, as well as increased costs for health care. It has been estimated that the nonhealth related costs associated with alcohol abuse reached ap-proximately $13 billion in 1992, owing in part to costs associated with crime committed while under the influence of alcohol. In summary, the annual cost of heavy drinking and alcohol-related disorders in the USA (both in dollars and in suffering) is enor-mous. Successful efforts to reduce the burden of illness attribut-able to alcohol could produce substantial reductions in the social, economic and personal costs of alcohol-related problems.