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Hazardous and Harmful Alcohol Consumption in Primary Care
M. Carrington Reid, PhD, MD;
David A. Fiellin, MD;
Patrick G. O'Connor, MD, MPH
Arch Intern Med. 1999;159:1681-1689.
ABSTRACT
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Increasing emphasis has been placed on the detection and treatment of hazardous and harmful drinking disorders, particularly among patients who are seen in primary care settings. In this review, we summarize the epidemiology and health-related effects of hazardous and harmful drinking and discuss current methods for their detection and treatment. Hazardous drinking is defined as a quantity or pattern of alcohol consumption that places patients at risk for adverse health events, while harmful drinking is defined as alcohol consumption that results in adverse events (eg, physical or psychological harm). Prevalence estimates range from 4% to 29% for hazardous drinking and from less than 1% to 10% for harmful drinking. Data from several recent large prospective studies suggest that alcohol consumption in quantities consistent with hazardous or harmful drinking may increase risk for adverse health events, such as hemorrhagic stroke and breast cancer. Existing screening instruments, such as the Michigan Alcoholism Screening Test (MAST) or the CAGE questionnaire, while excellent for detecting alcohol abuse or dependence, should not be used alone to screen for hazardous and harmful drinking. The Alcohol Use Disorders Identification Test (AUDIT) is currently the only instrument specifically designed to identify hazardous and harmful drinking. Treatment of these disorders in the form of brief interventions can be successfully accomplished in primary care settings, as demonstrated by a number of well-conducted randomized trials. Given its proven efficacy in the primary care setting, we recommend routine application of this treatment approach.
INTRODUCTION
Alcohol use disorders (AUDs) are a recognized cause of significant morbidity and mortality in the US population.1 These disorders are heterogeneous and include severe problems, such as alcohol abuse or dependence, as well as less severe disorders, often referred to as heavy, hazardous, or harmful drinking. Although alcohol abuse and dependence have historically received the greatest attention, increasing emphasis has been placed on the detection2-4 and treatment5-6 of less severe AUDs, particularly in primary care settings.2-6 This change in focus has occurred in part because of reports that heavy, hazardous, and harmful drinking are more common and may be more responsive to treatment2, 4 than alcohol abuse or dependence. In this article, we review the epidemiology and health-related effects of these drinking disorders and summarize current methods for their detection and treatment.
Table 1 lists the various categories of AUDs and their definitions as used in this review. These categories reflect the clinical reality that drinking problems occur over a broad continuum, ranging from alcohol consumption that can result in profound physical and psychological impairment (alcohol dependence) to less severe disorders (heavy or hazardous drinking).
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Table 1. Alcohol Use Disorder Definitions*
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DEFINITION OF HEAVY DRINKING
Heavy drinking is defined as a quantity of alcohol consumption that exceeds an established threshold value. The National Institute of Alcohol Abuse and Alcoholism sets this threshold at more than 14 drinks per week for men (or >4 drinks per occasion); more than 7 drinks per week for women (or >3 drinks per occasion); and more than 7 drinks per week for all adults 65 years and above.7 Individuals whose drinking exceeds these guidelines are thought to be at increased risk for adverse health events.2, 7-8
DEFINITION OF HAZARDOUS DRINKING
Hazardous drinking is defined as a quantity or pattern of alcohol consumption that places individuals at risk for adverse health events9 and is recognized by the World Health Organization (WHO) as a distinct disorder. The quantity or pattern of alcohol consumption that constitutes hazardous drinking is also typically specified by setting threshold values for an individual's average number of drinks consumed per week or per occasion. For example, in a recent study10 that examined the efficacy of the Alcohol Use Disorders Identification Test (AUDIT),9 hazardous drinking was defined as an average consumption of 21 drinks or more per week for men (or  7 drinks per occasion at least 3 times a week), and 14 drinks or more per week for women (or 5 drinks per occasion at least 3 times a week).
Because hazardous and heavy drinking are similarly defined (ie, a quantity or pattern of alcohol consumption that exceeds a specific threshold and may increase risk for adverse health events), we will use 1 term, hazardous drinking, to define this type of drinking disorder.
DEFINITION OF HARMFUL DRINKING
Harmful drinking is defined as alcohol consumption that results in physical or psychological harm. This disorder is also recognized by the WHO9 and is defined by criteria of the International Classification of Diseases, 10th Revision (ICD-10),11 which include (1) clear evidence that alcohol is responsible for physical or psychological harm, (2) the nature of the harm is identifiable, (3) alcohol consumption has persisted for at least 1 month or has occurred repeatedly over the previous 12-month period, and (4) the individual does not meet the criteria for alcohol dependence.
EPIDEMIOLOGY OF HAZARDOUS AND HARMFUL DRINKING
Prevalence estimates for hazardous and harmful drinking are shown in Table 2 and Table 3, along with information regarding the various study settings, populations, and definitions used to classify these disorders. Most of these studies also determined prevalence rates for alcohol dependence, and these data are reported for purposes of comparison. Unless noted, reported prevalence estimates for individual drinking disorders are mutually exclusive.
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Table 2. Prevalence Estimates for Alcohol Use Disorders From Population-Based Studies
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Table 3. Prevalence Estimates for Alcohol Use Disorders Among Medical Outpatients
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POPULATION-BASED STUDIES
Hilton12 surveyed more than 5000 adults in 1984 to determine the prevalence of alcohol disorders among US adults (Table 2). Hazardous drinking was reported by 18% of men and 5% of women, whereas prevalence rates for harmful drinking were 10% and 4% for men and women, respectively. In contrast, 7% of men and 3% of women had problematic drinking disorders and would likely have met the current diagnostic criteria for alcohol dependence. These prevalence estimates are not mutually exclusive. Among men classified as hazardous drinkers, 36% met the criteria for harmful drinking and an additional 27% were found to have problematic drinking disorders, whereas among women classified as hazardous drinkers, 44% fulfilled the criteria for harmful drinking and an additional 31% were classified as problematic drinkers.
Archer and Grant13 analyzed results from the 1988 National Health Interview Survey (NHIS), a population-based study of more than 40,000 US adults, and found that 54% of the participants reported current consumption of alcohol. Among current drinkers, 16% met the criteria for alcohol abuse or dependence (9% of the population studied), and 24% reported drinking at hazardous levels (13% of the population studied). In the NHIS, approximately 50% of all current drinkers who were classified as having alcohol abuse or dependence also fulfilled the criteria for hazardous drinking. In a separate study of all NHIS participants (N=41,128), Grant14 determined the prevalence of alcohol dependence and harmful drinking using different diagnostic criteria. In this study, prevalence rates for alcohol dependence and harmful drinking were 7% and 0.3%, respectively. Finally, Dawson et al15 determined that among adults surveyed in the 1992 National Longitudinal Alcohol Epidemiologic Study (N=42,862), 14% of men and 4% of women reported drinking at hazardous levels.
MEDICAL OUTPATIENT STUDIES
McMenamin16 screened 611 primary care patients aged 30 to 69 years for alcohol disorders using a self-administered questionnaire that measured quantity and frequency of consumption as well as alcohol-related problems (Table 3). Six percent of the subjects met the criteria for alcohol abuse or dependence and 15% were classified as hazardous drinkers. Adams et al8 screened more than 5000 older adults aged 60 years and above in 22 primary care practices with standard quantity-frequency questions and the CAGE questionnaire. Fifteen percent of men and 12% of women were classified as hazardous drinkers, and 9% and 3% of men and women, respectively, screened positive for dependent drinking. In this study, 14% of all hazardous drinkers also met the study criteria for alcohol dependence. Piccinelli et al10 determined the prevalence of hazardous, harmful, and dependent drinking among 482 primary care patients using the AUDIT and ICD-10 criteria as the criterion standard. Hazardous drinking was reported by 29% of men and 4% of women. The prevalence of harmful alcohol consumption was 7% among men and less than 1% in women, whereas fewer than 2% of subjects (all men) were alcohol dependent.
Volk et al17 employed the AUDIT and the Alcohol Use Disorder and Associated Disabilities Interview Schedule as the criterion standard to ascertain the prevalence of hazardous, harmful, and dependent drinking among 1333 primary care patients with different racial and ethnic backgrounds. Prevalence rates for hazardous drinking ranged from 4% to 5% to 9% for white, African American, and Mexican American men, respectively, and from 4% to 3% to 2% for women in each of the 3 subgroups, (R. J. Volk, PhD, written communication, November, 1998). In contrast, prevalence estimates for harmful drinking were 1% or less across the 3 subgroups.17 The most common drinking disorder encountered was alcohol dependence,17 with prevalence rates that ranged from 11% to 12% to 14% among African American, Mexican American, and white men, and from 7% to 6% to 5% for women among the 3 subgroups (R. J. Volk, PhD, written communication, November 1998).
These data suggest that hazardous drinking is common among US adults and medical outpatients, with prevalence estimates varying from 4% to 29%. The wide variation in reported prevalence for hazardous drinking is probably caused by differences in the way the disorder was defined and lack of mutually exclusive diagnostic criteria. Prevalence rates for harmful drinking, in contrast, ranged from 0.3% to 10%. Although harmful drinking is thought to be more prevalent than alcohol dependence,2 published prevalence estimates do not support this view. One potential explanation for this unexpected finding is that the current diagnostic criteria (ICD-10) for harmful drinking may have excellent specificity, but may not be sufficiently sensitive to detect less severe manifestations of alcohol-related problems. Demonstrating clear evidence of physical (eg, gastrointestinal hemorrhage) or psychological (eg, depression) harm may be difficult, except in severe cases (ie, alcohol dependence).
In general, these studies support recommendations that call for increased attention to less severe AUDs, particularly hazardous drinking. Additional studies are needed to further define the extent and spectrum of hazardous and harmful drinking in primary care settings. To promote effective comparisons, future investigations should use similar diagnostic criteria and ensure that mutually exclusive prevalence estimates are reported for the entire spectrum of drinking disorders.
HEALTH-RELATED EFFECTS
Alcohol intake of more than 6 drinks per day increases the risk for numerous adverse health events.18-20 In contrast, the adverse effects of alcohol consumption in quantities above 2 (but <6) drinks per day have received less attention. Most patients drinking at hazardous or harmful levels would likely sustain this intermediate level of alcohol exposure. Accordingly, we reviewed large (N>1000) observational cohort studies published between 1988 and 1998 that provided risk estimates for the independent effect of alcohol intake across this range of exposure on 3 outcomes: all-cause mortality, stroke, and breast cancer. Although the number and type of potential confounders examined in these studies21-43 varied considerably, age and smoking status were included in all analyses.
ALL-CAUSE MORTALITY
At least 13 large prospective studies21-33 have evaluated the relationship between alcohol consumption and all-cause mortality. In general, these studies found either a U- or J-shaped association between alcohol consumption and all-cause mortality for both sexes, where categories of exposure ranged from none to 6 drinks or more per day. Statistically significant risk estimates were reported in 6 studies,21, 23-24,27, 31, 33 (relative risk [RR] range, 1.2-2.2), whereas 2 investigations25-26 found that alcohol exposure of 2 drinks or more a day significantly lowered overall mortality. These estimates fail to provide important information about cause-specific mortality; for example, deaths from cardiovascular disease were on average lower across these exposure categories,24, 26, 28-29 while mortality rates from various cancers21, 24, 27, 29, 31-32 and fatal injuries24, 29, 31 were substantially increased.
STROKE
Five recent large prospective studies34-38 examined the association between alcohol consumption and stroke. Two studies34, 37 found increased risk for ischemic stroke among subjects who drank 2 drinks or more per day; however, in only 1 was statistical significance demonstrated (RR, 2.0).37 Of the remaining 3 studies, 1 found no effect,35 while 236, 38 found nonsignificant protective effects. Alcohol consumption of 2 drinks or more per day, however, may increase the risk for hemorrhagic stroke. Statistically significant increases in risk (RR range, 3.1-3.9) were reported by 2 studies36-37 that examined the relationship between alcohol intake and hemorrhagic stroke.
BREAST CANCER
Drinking 3 drinks or more per day may increase the risk for breast cancer, as demonstrated in 5 large prospective studies.39-43 Statistical significance was demonstrated in 2 of these investigations40, 43 (RR range, 1.6-3.3), whereas in 3 studies,39, 41-42 nonsignificant increases in risk were found. Given the public health importance of this cancer, women drinking 3 drinks or more per day should be counseled to reduce their alcohol intake, even though a causal connection has not been definitively established between alcohol consumption and breast cancer.
These data suggest that alcohol-related morbidity and mortality may occur at doses below those typically considered diagnostic of alcohol abuse and/or dependence. Alcohol consumption of 2 drinks or more per day may also increase the risk for the development of hypertension,44-45 traumatic injuries,46-47 and adverse drug-alcohol interactions,48-49 and may impair an individual's social and occupational functioning. The absolute magnitude of this effect, however, can vary widely by outcome. Additional research is needed to define the health-related effects of hazardous and harmful drinking in primary care populations.
METHODS OF DETECTION
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