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MENTAL AND NEUROLOGICAL PUBLIC HEALTHA Global Perspective
Academic PressCopyright © 2010 Elsevier Inc.
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Chapter OneSECTION 1 EPIDEMIOLOGY
Alcohol Consumption: Overview of International Trends
Alcohol consumption is linked to over 60 health conditions and the related burden of disease is high; it ranks as the fifth most important risk factor for the burden of disease worldwide (Rehm et al., 2003b); (WHO, 2002) and ranked first in the region of the Americas for the year 2000 (Rehm and Monteiro, 2005). There is ample evidence that the overall consumption of alcohol in a population is a good proxy for the percentage of heavy drinkers in that population. Overall consumption is related to all-cause mortality and alcohol-specific mortality and disability (Edwards et al., 1994); therefore, changes in consumption lead to changes in the overall as well as the alcohol-specific disease burden in a population. As a result, national and international trends in alcohol consumption are related to disease outcomes and serve as monitoring tools of policy changes at country, regional, and global levels.
Two Dimensions of Alcohol Consumption
There are two dimensions of alcohol consumption: average volume of consumption and patterns of drinking, both of which are related to disease burden (Rehm et al., 2003). Average volume, or per capita consumption, is related mostly to long-term health consequences, including alcohol dependence. Although average volume is also related to acute consequences, such as injuries, several studies indicate that the ability to predict such injuries is increased by taking patterns of drinking into account (Rehm et al., 1996). For example, the same average volume of consumption (1 drink per day) can be consumed in one day of the week (7 drinks on one occasion) or through daily drinking (1 drink per day over 7 days), and the expected outcomes are different. In other words, how an individual drinks, which is influenced by cultural context, can moderate the impact of average volume of consumption on mortality and morbidity.
The pattern of drinking (how, when, and how much is consumed) has been related to acute health outcomes such as injuries and also to chronic diseases such as coronary heart disease and sudden cardiac death (Rehm et al., 2006).
As part of the World Health Organization (WHO) Comparative Assessment of Risk Factors for the Global Burden of Disease study (2000), both dimensions of alcohol consumption for different regions of the world were quantified. It is beyond the scope of this article to cover details of such study, which can be found in other publications (Rehm et al., 2003a, b). This article provides an overview of some methodological issues regarding these two dimensions relevant for comparative studies at the national level, and presents an international trend analysis as well.
The WHO has recently updated international guidelines for monitoring alcohol consumption and related harm (WHO, 2000). This guide provides details on how to calculate per capita consumption and related harms, including limitations and problems in interpreting the data. It should be consulted when planning to collect and use national and international estimates.
Estimating Per Capita Consumption by Country
Estimating the average volume of alcohol consumption in a country is best made using national sales and production and/or taxation data, as population surveys invariably underestimate total alcohol consumption. Retail sales data are the most accurate means of estimating how alcohol is consumed in a population, as governments often monitor sales data for tax collection purposes. Although there are some limitations to this type of data (e.g., beverages can be purchased yet not consumed in the same year, stockpiling can occur before a tax increase, neither home production nor smuggling is accounted for), it is still a relatively reliable source.
When gathering these data, the three major categories of alcoholic beverages (beer, wine, and distilled spirits) available within a country should be included in the estimates. In many developing countries, however, local beverages are as important as the three major categories (e.g., cider, fruit wines, shochu, aguardiente, cachaca, samsu) but often do not fall into the other categories or are sold in informal markets or are not taxed. Therefore, additional survey data can provide information on who drinks what type of beverages (at least by gender and age groups), which can then be useful in monitoring trends in consumption and relating specific beverages to specific harms.
Per capita consumption figures are given in liters of pure alcohol, which require estimates and/or assumptions about alcohol content of different beverages. Beer, for example, is usually estimated at 5% pure alcohol, but it can vary from 0.9 to 12%. As there is no international standard, countries should make periodic efforts to estimate median alcohol content of each beverage category as they can vary widely from country to country as well as within regions of the same country.
According to WHO recommendations, the total estimated adult alcohol consumption for a country is equal to the total alcohol production plus alcohol imports minus alcohol exports (in the same year) divided by the total population of 15 years of age and over. However, in calculating the average consumption of the total population there may be an underestimate of consumption, particularly in developing countries in which a large proportion of the population is under 15 years of age.
Market research firms serving the alcoholic beverage industry, or industry associations are a good source of data (e.g., Impact Databank, World Drink Trends, Statistical Handbook); however, these data are expensive to obtain and therefore of limited use by governments or researchers. These publications do not cover all countries, especially developing countries, and the information is often not reliable. However, in the absence of any other more reliable source of information, they can be used to supplement data at country and international levels.
The impact of tourism can also be substantial, and some estimate of the size of the tourist population in a given year (15 years of age and older) can be used for estimating adult per capita consumption for a country. If there are special sales taxes or measures for alcoholic beverages sold to tourists that can distinguish them from local consumption, the estimates can be done more adequately.
The United Nations Food and Agriculture Organization (FAO) publishes the most complete set of statistics available on the production and trade of beer, wine, and distilled spirits, and this set can be used in the absence of sales data. These statistics are collected from annual questionnaires sent to ministries of agriculture and trade (they are also available to the public on the FAO's website, see under 'Relevant Websites' section). The data consist of estimates of production and trade in metric tons for wine; vermouth; must of grape; fermented beverages; spirits; sorghum, millet, maize, and barley beer; and wheat-fermented and rice-fermented beverages. Beverage data are converted into metric tons of pure alcohol and then all beers are combined into a single beer category, all wines into a wine category, and all spirits into a 'beverages, alcoholic' or distilled spirits category (WHO, 2000). However, the data rely on national reporting (and not all countries are included) and do not include estimates of unrecorded consumption (e.g., home production, duty-free alcohol, smuggling). Nonetheless, the FAO remains the most comprehensive international data source on production of alcoholic beverages. Caution needs to be taken, however, in interpreting the data. Because only large-scale industrial production is quantified, data for countries with substantial informal, low-technology, or home production will be underestimated, as is the case with several African countries. In addition, when data are missing, the gaps are filled with repeated information of the last year reported. As the country population grows, per capita consumption may artificially decline, thus providing a false trend (WHO, 2000).
Estimating Levels of Consumption and Patterns of Drinking
General population surveys can provide a wide range of information on where drinking takes place, patterns of consumption, sociodemographic correlates, and alcohol-related harms. At the simplest level of analysis, they can provide information regarding, for example, the number of abstainers in the population in the last 12 months, lifetime abstainers, and consumption of alcohol by gender. There is variation worldwide on the rates of abstinence for men and women. There are countries in which the rate of abstinence is very high for both genders (e.g., where drinking is prohibited for religious reasons), and countries in which most of the drinking is done by males, with females drinking relatively less. Some European countries present no differences between genders. When rates of abstinence are considered, the average amount of alcohol consumption per drinker can be much greater than expected.
Population-level data cannot, however, identify different drinking patterns in a population, who does the drinking (e.g., which age groups), how patterns relate to socioeconomic characteristics of the population or to gender, where the drinking takes place, when and how it is consumed, if it is concentrated into special occasions of high consumption, such as in festivals or holidays, or is more evenly distributed throughout the year.
Surveys can also indicate the prevalence of high-, moderate-, and low-risk drinkers, according to clearly defined criteria. Patterns of drinking are not uniform across different studies thus, for the global burden of disease study, patterns of drinking have to be defined and estimated. A key informant questionnaire was sent to countries and, after two surveys, data were obtained from 63 countries in all regions but the Eastern Mediterranean. Four different aspects of drinking were covered by the survey: heavy drinking occasions (e.g., festive drinking at fiestas or community celebrations, the proportion of drinking occasions in which drinkers get drunk, the proportion of drinkers who drink daily or nearly daily, drinking with meals, and drinking in public places.
The results of this and other such surveys were combined with available national or regional survey results (unpublished information or publications in peer-review journals). They were then analyzed using optimal scaling analysis, which is similar to factor analysis but permits the simultaneous inclusion of ordinal and categorical data, to determine the number of underlying dimensions and the relations of items to each dimension. The analysis identified one dimension called a detrimental impact that leads to increased mortality and morbidity.
The countries were then classified into four categories and assigned values from 1 (least risky drinking pattern) to 4 (most risky drinking pattern). Rates of abstention were taken into account separately in the final comparative risk analysis (for the final algorithms for calculating pattern scores, see Rehm et al., 2003b).
Rates of a variety of alcohol-related problems can be explored by surveys and linked to patterns of drinking and amount or frequency of drinking. Information on alcohol use disorders, using validated instruments such as AUDIT (Babor et al., 2001) and CAGE (Ewing, 1984), and diagnostic criteria such as those found in the ICD-10 or DSMIV, can be of value. This information is important when assessing coverage of treatment services in a particular country and then planning the organization of health treatment systems to respond to the range of alcohol-related problems.
On surveys, the most used and recommended questions regarding alcohol consumption are quantity-frequency, graduated frequency, and recent recall (WHO, in press). Even though there is still little agreement in the literature on which questions to include in surveys, and how to ask them, international collaborative studies have tried to increase comparability of data by agreeing on common indicators on a core number of areas, thus some progress has been made. Two studies are the GENACIS study (Gender, Alcohol, Culture: An International Study), which included 35 countries from most regions of the world and assessed alcohol consumption and related problems from the adult general population, and the ESPAD (European School Survey Project on Alcohol and Drugs), which collected information from school students 13–15 years of age in European countries in 1995, 1999, and 2003, using the same basic questionnaire.
There are numerous methodological issues to be considered when planning, undertaking, and interpreting data from surveys. These include reference period, beverage-specific or overall questions on consumption, quantity per drinking day versus quantity per drinking occasion, drink size and alcohol content of alcoholic beverages (and mixed drinks), criteria for defining a drinker or non-drinker, validity and reliability of the survey instrument in the absence of international standardization, criteria for risk drinking (on a single occasion and average daily consumption, for acute or chronic problems), sample selection, and sample size, among others. The WHO guide (2000) is a good source of information on these methodological issues and how to address them.
WHO Alcohol Database
Although several attempts have been made in the past at summarizing world and regional drinking trends from a public health perspective, a key initiative from the WHO has become the most comprehensive source of data on alcohol in the world. In 1996, the WHO organized the Global Alcohol Database, bringing together the most reliable and updated information on alcohol consumption and related harm by country. It was created by the Marin Institute for the Prevention of Alcohol and Other Drug Problems, and maintained for some time by the Swiss Institute for the Prevention of Alcohol Problems. It is currently hosted and maintained by the Centre for Addiction and Mental Health in Toronto, Canada. Data from recorded production are included as well as data from national surveys and estimations of unrecorded consumption, health effects, national alcohol policies, and interventions. The database has information from the majority of countries in the world, although there are many gaps in the validity and reliability of the information.
In 1999 the WHO published the first Global Status Report on Alcohol, which included estimates of adult per capita consumption for most countries, relying on a combination of national and regional estimates, industry data, and data from the FAO and the UN Statistical Office (WHO, 1999). In 2001, it published the Global Status Report: Alcohol and Young People (WHO, 2001). In 2004, WHO (2004a) published the Global Status Report: Alcohol Policy and the Global Status Report on Alcohol 2004 (2004b). The latter publication provided time-series analysis from 1961 to 2001 for all beverages, and also for beer, spirits, and wine separately, in liters of pure alcohol per adult per year in each country. Data regarding alcohol consumption from cross-border shopping, smuggling, legal or illegal home production (unless included in FAO estimates), or tourists were not included, however, estimates were given for recent years for many countries. The adult per capita consumption estimates were based on either FAO or World Drink Trends data, except for a few countries in which data were available directly from governments. The WHO estimates of adult per capita consumption are regularly updated, in support of WHO initiatives and global burden of disease calculations.
The following section illustrates some examples of uses of the WHO database for analyzing international trends in alcohol consumption, globally and regionally. Data available up to 2003, in most cases, were used for all analysis. Even though there are methodological limitations inherent in the data, the results still provide interesting and useful information.
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