world cancer report - iarc

users, that is, active smokers. The prevalence
of smoking varies throughout the
world and is subject to change (Fig. 2.8). The
proportion of smokers is decreasing among
men in industrialized countries. More than
70% of men born in Europe and North
America during the first decades of the 20th
century smoked during some time of their
life, but this proportion has decreased in
more recent times. There is an increasing
Production Import Export
Location (tonnes/annum) (tonnes) (tonnes)
USA 890,240 234,910 266,104
Europe 760,086 772,675 319,568
Russia 290,000 86,000 2,200
Africa 274,624 85,989 187,208
China 2,000,000 80,000 10,000
India 525,000 100 104,862
Global 6,660,000 1,512,638 1,484,144
Table 2.1 Tobacco production, imports and exports. In some regions, such as Africa and India, the export
of tobacco is a major source of income.
Fig. 2.2 Magazine advertising in the1970s directed towards women in the USA.
proportion of ex-smokers in many countries,
particularly within older age groups.
A different pattern is seen in women. In
contrast to male smoking rates, smoking
by women only became prevalent in the
second half of the 20th century. While in
some countries, such as the United
Kingdom, the proportion of women who
smoke has started to decrease in recent
years, in most industrialized countries this
proportion is still increasing [4].
In developing countries, less comprehensive
data are available. It is clear, however,
that a great increase in smoking has taken
place during the last decade in many countries.
The increase is particularly dramatic
in China, where more than 60% of adult
men are estimated to smoke, representing
almost one-third of the total number of
smokers worldwide. The prevalence of
smoking among women in most developing
countries is still low, although in many
countries young women are taking up the
habit. In India and its neighbouring countries,
smokeless tobacco is widely used
and “bidi” smoking is also common, this
being the cheapest form of smoking available.
Non-smokers are exposed to environmental
tobacco smoke, the extent of exposure
being determined primarily by whether
family members smoke and by workplace
conditions. The amount of tobacco smoke
inhaled as a consequence of atmospheric
pollution is much less than that inhaled by
an active smokers [5].
Cancer risk
Tobacco smoking is the main known
cause of human cancer-related death
worldwide. Smoking most commonly
causes lung cancer [6]. For a smoker, lung
cancer risk is related to the parameters of
tobacco smoking in accordance with the
basic principles of chemical carcinogenesis:
risk is determined by the dose of carcinogen,
the duration of administration
and the intensity of exposure. In respect
of these determinants of lung cancer risk,
women are at least as susceptible as men.
An increase in risk of lung cancer (relative
to a non-smoker) is consistently evident at
the lowest level of daily consumption, and
is at least linearly related to increasing
Tobacco 23