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Alcohol

4. What are the health effects of alcohol consumption?

  • 4.1 What diseases are due to alcohol consumption?
  • 4.2 What are the effects of alcohol on the unborn child/fetus?
  • 4.3 What are the health benefits of alcohol consumption?
  • 4.4 How are depression and alcohol consumption linked?
  • 4.5 In what ways can alcohol consumtion lead to physical injuries?
  • 4.6 What is the overall health burden of alcohol consumption?

Alcohol can cause social effects and health effects (both physical and mental).

Social effects are for instance those that affect the behaviour of individuals, or how they interact with others. Although mainly health effects of alcohol are discussed here, it is important to note that social harm has a major impact on well-being, even if it cannot be easily quantified.

Health effects of alcohol have been observed in nearly every organ of the body. Indeed alcohol consumption has been linked to more than 60 diseases.

The effects of alcohol on health and well-being can manifest themselves as chronic disease, accidents and injuries, as well as short-term and long-term social consequences. Both the amount of alcohol consumed and the pattern of drinking determine whether there will be:

Figure 4
Figure 4
: Model of alcohol consumption, mediating variables, and short-term and long-term consequences

Biochemical effects of moderate consumption can be beneficial, such as protection against coronary heart disease, but more usually harmful, leading for instance to damage to the pancreas.

Intoxication is strongly linked to accidents, injuries, deaths, domestic conflict and violence.

Alcohol dependence is a powerful mechanism that sustains alcohol consumption and its short-term and long-term consequences.

Some diseases, such as alcohol dependence, are clearly fully attributable to alcohol. Others, such as cirrhosis of the liver are mainly attributable to alcohol, while others, such as breast cancer, are only partly attributable to alcohol. The extent to which alcohol contributes to a disease is expressed in “alcohol attributable fractions” (AAFs). In a similar way, it is possible to establish the AAF for road traffic accidents, based on the alcohol concentration in the driver’s blood.

This text is a summary of: WHO Global Status Report on Alcohol 2004
 Consequences of alcohol use, Health effects and global burden of disease, p.35-57

4.1 What diseases are due to alcohol consumption?

A number of disease conditions are wholly attributable to alcohol. These include alcoholic psychoses, alcohol-dependence syndrome, as well as some diseases affecting the nerves (alcoholic polyneuropathy), the heart (alcoholic cardiomyopathy), the stomach (alcoholic gastritis), and the liver (alcoholic liver cirrhosis).

Alcohol can cause a number of different cancers:

  • The risks of developing lip, tongue, throat, oesophagus and liver cancer increases proportionally with the amount of alcohol consumed.
  • Even moderate alcohol consumption can cause breast cancer, according to recent research, and a series of studies confirm that the risk increases with the amount consumed.
  • Evidence of a possible link with alcohol consumption is weaker for cancers of the stomach, prostate, colon, rectum and ovaries
  • There is no established relationship between alcohol consumption and cancer of the salivary glands, uterus or bladder.

Alcohol can have both a damaging role and a protective role in the development of cardiovascular disease. Alcohol consumption, particularly heavy drinking occasions, can contribute to high blood pressure, abnormal heart rhythms, heart failure, and strokes. At low levels of consumption (less than 40g of pure alcohol per day) without heavy drinking occasions alcohol may protect against strokes, at least in women. This is equivalent to 3 small glasses of wine or 1 litre of beer per day. Above this limit, the risks of cardiovascular disease increase dramatically.

Alcohol is the main cause of liver cirrhosis in developed countries. However, in China and India, for instance, liver cirrhosis is mainly caused by other factors such as viral infections. The fraction of liver cirrhosis attributable to alcohol ranges from as low as 10% in China, up to 90% in Finland. It is very difficult to determine whether an individual’s cirrhosis is induced by alcohol or by other unspecified causes, and a considerable proportion of deaths from cirrhosis in which alcohol is not mentioned may in fact be attributable to alcohol. Apparently the risk of liver cirrhosis mainly depends on the volume of alcohol consumed, but possibly also on heavy drinking occasions.

Alcohol appears to contribute to causing depression. Moreover, alcohol dependence and other mental conditions often go hand in hand, though the role of alcohol in these conditions remains unclear.

To what extent different drinking habits can affect the risk of developing major chronic disease has been estimated for men and women.

This text is a summary of: WHO Global Status Report on Alcohol 2004
 Harmful effects of alcohol consumption excluding depression and coronary heart disease, p.37-40

4.2 What are the effects of alcohol on the unborn child/fetus?

pregnant woman
© Micro Applications

The fetus is at risk when the mother consumes alcohol during pregnancy.

The risks include overt birth defects and a less obvious group of effects known as Fetal Alcohol Spectrum Disorders (FASD). Disorders may range from minor anomalies, for example of the face, through to adverse effects on brain development, including mental retardation.

Alcohol consumption during pregnancy can also cause spontaneous abortion, slower fetal growth in the womb, premature birth and low birth weight.

This text is a summary of: WHO Global Status Report on Alcohol 2004
 Effects of prenatal alcohol exposure, p.39

4.3 What are the health benefits of alcohol consumption?

Moderate alcohol consumption has been shown to lower some specific health risks.

Strokes occur when brain cells die because of inadequate blood flow, most commonly:

On the one hand, low to moderate alcohol consumption may offer some protection against ischaemic stroke. On the other hand, alcohol consumption increases the risk of haemorrhagic stroke.

Large studies on human populations show that moderate alcohol consumption may offer some protection against diabetes. The protective effect is probably due to the known actions of alcohol on glucose tolerance and insulin resistance, both of which are factors involved in the development of diabetes. Nevertheless, high levels of alcohol consumption may actually increase the risk.

There is also some evidence from large-scale studies that alcohol may offer some protection against the formation of gallsrones.

Table 13: Relative risks for beneficial alcohol-related health effects for different drinking categories (compared to abstainers)

Low to moderate levels of alcohol consumption can reduce the risk of coronary heart disease, one of the leading causes of death in the world. Most of the protective effect is gained by consumption of as little as one drink every other day. However, when people consume higher levels of alcohol, the risk of coronary heart disease is greater than when they abstain from drinking altogether. The protective effect is thought to be mainly due to changes in blood fats, especially increases in benefical high-density lipoproteins, but also to beneficial effects on blood clotting, dilation of blood vessels, insulin resistance, hormones such as estrogen, and inflammatory processes. Most of these protective effects are attributed to alcohol itself but possibly also to other substances contained especially in wine.

Meal and wine
Meal with wine

Low to moderate alcohol consumption appears to be more protective when consumption is predominantly with meals, as opposed to outside meals. This may be due to the reduction in blood pressure that follows eating, a beneficial effect on clotting, slower absorption of alcohol or faster elimination of alcohol.

In contrast, irregular heavy drinking occasions, such as consumption of more than 8 drinks in one sitting, have an adverse effect on coronary heart disease and are linked to sudden deaths from heart attack. This is thought to be related to the tendency for high amounts of alcohol to increase blood clotting and to impair the beating of the muscles of the heart that pumps the blood around the body. Irregular heavy drinking occasions also increase the amount of non-beneficial, low-density lipoproteins in the blood and increase the likelihood of adverse changes to the heart muscle and the nerves supplying the heart muscles. Thus, irregular heavy drinking appears to have opposite effects from low to moderate drinking.

This text is a summary of: WHO Global Status Report on Alcohol 2004
 CHD as a chronic condition where alcohol has harmful and beneficial consequences, p.40-43

4.4 How are depression and alcohol consumption linked?

The relationship between alcohol and mental disorders was not well studied until recently. However, there is sufficient evidence to assume that alcohol plays a role in causing depression.

depresion
Individuals often suffer from alcohol problems in combination with depression

Alcohol dependence and major depression occur together, both within short time periods, such as a year, and over a lifetime. The higher the amount consumed, the greater the number of symptoms of depression. Compared to the general population, depression is seen more frequently in patients being treated for alcohol abuse or dependence. Similarly, a higher frequency of alcohol-related disorders is seen in patients being treated for depression.

In individual cases, it is often not clear if alcohol caused depression, if depression caused alcohol problems, or if both might have been caused by a third factor. Yet, many countries show a certain proportion of cases of depression in which excessive alcohol use precedes the depression, which suggests alcohol may be the cause. Moreover, depression symptoms tend to decrease or disappear during alcohol abstinence, confirming that alcohol may be the cause.

This text is a summary of: WHO Global Status Report on Alcohol 2004
 Consequences of alcohol use, Health effects and global burden of disease, Depression, p.43-45

4.5 In what ways can alcohol consumtion lead to physical injuries?

Alcohol goes along with increased risk of physical injury from road accidents, falls, fires, sports and recreation, self-inflicted injuries and violence. The presence of alcohol in the body may also aggravate injuries.

Alcohol causes unintentional injuries, mainly through traffic accidents, because it affects reaction times, thought processing, coordination and vigilance. A large review has shown that tasks involving coordination between the brain and muscular action start to be affected above a blood alcohol level of 40 to 50 mg% (0.04%-0.05%).

The risk of unintentional injury increases with the level of alcohol consumption, even at relatively low levels. The risk of injury is greatest when individuals consume much more than they normally do. In summary, the amount of alcohol consumed, and more specifically the actual blood alcohol content, determines the likelihood of unintentional injury.

Alcohol consumption is also strongly associated with intentional injuries caused by aggressive behaviour leading to violent crime. Drinking frequently precedes violent incidents and the severity of the violence is related to the amount of drinking beforehand.

Different effects of alcohol contribute to increased likelihood of aggressive behaviour. Effects of alcohol on the brain can reduce the anxiety about the consequences of one’s actions. They also impair thinking and problem solving ability in situations of conflict and result in overly emotional responses. Other effects of alcohol on behaviour include a resolute focus on the present (alcohol myopia) and a need to affirm personal power, at least for men.

Table 15: Attributable fractions of acute alcohol-related health effects in the adult general population

This text is a summary of: WHO Global Status Report on Alcohol 2004
 Consequences of alcohol use, Health effects and global burden of disease, Depression, p.46-48

4.6 What is the overall health burden of alcohol consumption?

In terms of lives lost, the benefits of alcohol consumption may outweigh its detrimental effects in some countries. Indeed, the number of deaths “prevented” by alcohol in some age groups may be greater than the deaths caused by alcohol. This is mainly due to the beneficial effect of low and moderate alcohol consumption on diseases of the heart and blood vessels. It applies mainly to developed countries with high life expectancy where moderate amounts of alcohol are regularly taken with meals.

However, in terms of life years lost, a different picture emerges. Indeed, fewer years are gained by preventing heart disease in the elderly than are lost because of premature death at an early age, say from traffic accidents.

The global health burden of alcohol consumption is even more negative when it takes into account years spent living in disability. In terms of “disability adjusted life years” (DALYs) lost, 4% of all years lost in 2000 are attributed to alcohol consumption, compared to only 3.5% in 1990.

There are regional differences in the relative importance of the overall disease burden from alcohol, because of different patterns of consumption and risk factors other than alcohol.

  • The disease burden is highest in developed countries (9.2% in 2000), where it is only exceeded by the burden attributable to tobacco and high blood pressure.
  • It is lower in developing countries with relatively low adult and infant mortality, where it is the main contributor to disease burden (6.2%),
  • It is lowest in developing countries with high mortality rates (1.6% in 2000), where undernutrition, unsafe sex, and unsafe water, sanitation and hygiene are more important risk factors.

Globally, the burden of alcohol-attributable diseases is greater among men than among women.

                     

Table 16: Global burden of disease in 2000 attributable to alcohol
according to major disease categories

Table 17: Burden of disease in 2000 attributable to tobacco, alcohol and drugs
by developing status and sex

Table 18: Characteristics of adult alcohol consumption in different regions of the world

Table 19: Alcohol-related harm in different regions of the world

Table 20: Selected population alcohol-attributable fractions
by disease category, sex and level of development

Table 21: Mortality rates for acute and chronic disease and injury
by WHO regional subgroupings

This text is a summary of: WHO Global Status Report on Alcohol 2004
 Consequences of alcohol use, Health effects and global burden of disease, Depression, p.50-58


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