world cancer report - iarc

ALCOHOL DRINKING
SUMMARY
> Heavy alcohol drinking causes cancer of
the oral cavity, pharynx, larynx, oesophagus,
and liver, and may increase the
risk of breast and colorectal cancer.
> Risk is linearly related to the mean daily
consumption.
> Low levels of consumption appear to
exert a protective effect against cardiovascular
disease.
> In the oral cavity, pharynx, larynx and
oesophagus, the risk is greatly
increased by concurrent smoking.
Beverages containing alcohol (the common
name for ethanol) as the product of
the fermentation of carbohydrates have
been produced in most human societies
since ancient times. Despite great variety,
most alcoholic beverages can be grouped
as either beers (brewed by fermenting
malted barley and typically containing 5%
volume of alcohol), wines (made by fermenting
grape juice or crushed grapes,
containing 12% alcohol) or spirits (made
by distilling fermented products of a variety
of cereals, vegetables and fruits, containing
40% alcohol). Beverages that are
less common and which are often limited
to particular regions include cider, fortified
wines and flavoured wines.
On a global scale, the consumption of
alcoholic beverages by adults as calculated
from official figures is equivalent to 4 L
of alcohol per year (or 9 g/day), corresponding
to approximately 3% of the average
total intake of calories [1]. Unofficial
consumption, however, is estimated to
account for an additional amount corresponding
to 20-100% of the official
figures, depending on the country. Most
“unofficial” alcohol is either sold illegally
on the black market (usually to avoid taxation)
or produced for private consumption.
There is strong regional variability in
consumption levels, with a minimum
(12 L/year) in Central and Southern
Europe. The distribution between each
major type of beverage is also countryspecific
(Fig. 2.10). Official figures show a
decrease in alcohol consumption in more
developed countries and, over recent
years, an increase in consumption in less
developed countries.
Cancers caused
Through analytical epidemiological studies
of cohort and case-control type conducted
in many populations with different
levels of consumption, the causal association
of drinking alcohol has been definitely
established in respect of oral,
oesophageal, liver and other cancers [2].
In particular, studies of cancer risk in
brewery workers and in alcoholic patients
have provided important evidence on the
carcinogenic role of alcohol. A causal
association is also established in the case
of breast cancer and is probable for colon
and rectal cancer [2,3]. There have been
suggestions of a possible carcinogenic
effect of alcohol drinking on other organs,
such as the lung, but the evidence is still
inconclusive [4]. An association between
alcohol intake and risk of head and neck
cancer is indicated by the geographical
pattern of these neoplasms; countries
(and regions within countries) with heavy
alcohol consumption are among those
with the highest incidence of these neoplasms.
For all cancers caused by drinking alcohol,
the risk of cancer is a linear function of
the level of consumption, up to an intake
of about 80 g/day (one litre of wine, a
quarter of a litre of spirits), above which
Mean alcohol Relative risk
consumption (95% confidence)
No alcohol 1
> 0 to 30 g/day 1.2 (0.4–3.4)
> 30 to 60 g/day 3.2 (1.0–10.1)
> 60 g/day 9.2 (2.8–31.0)
*Adjusted for follow-up time, sex, education, body mass
index (BMI), vegetable and fruit consumption, tobacco
smoking and energy intake
Table 2.4 Consumption of alcohol increases the
risk of cancer of the upper gastrointestinal tract.
Fig. 2.10 Patterns of alcohol drinking, expressed as mean equivalent volumes of pure ethanol, in selected
countries, 1996.
Alcohol drinking 29