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4. Smoking of Tobacco
Special enquiries into the smoking habits of cases of lung cancer in many countries
show there is:-
(a) a higher mortality in smokers than in non-smokers,
(b) a higher mortality in heavy smokers than in light smokers,
(c) a higher mortality in cigarette smokers than in pipe smokers,
(d) a higher mortality in those who continued to smoke than in those who gave it up.
Males who smoke heavily have a death rate from lung cancer forty times that of nonsmokers.
Death from lung cancer is likely to occur in one out of every eight heavy smokers but
only in one out of every 300 NON-smokers.
Recently, dramatic evidence has been obtained from the Channel Island of Jersey. There,
tobacco is very much cheaper than in England and Wales and the average death rate from lung
cancer over the three years 1957 - 1959 was 935 per million for men and 167 for women. These
figures give Jersey the highest male lung cancer death rate in the world and an exceptionally
high rate for women, possibly only exceeded by that for Mexico. More tobacco perhead per population
is smoked in Jersey than anywhere else in the world and, due to the non-industrial nature of the
island, atmospheric pollution is virtually non-existent. Most important of all is the fact that no
case of lung cancer occurred in a non-smoker.
5. Cancer Causing Factors in Tobacco Smoke
Five substances capable of causing cancer have been isolated from tobacco smoke. The
amounts present are very small but their mere presence is suggestive.
6. Atmospheric Pollution
There is a higher mortality from lung cancer in urban areasthan in rural. Cancer producing
materials are found in smoke from coal and in motor vehicle exhaust gases.
No evidence exists to show that transport workers, garage hands and policemen, who are
specially exposed to vehicle exhaust fumes, suffer from lung cancer more frequently than other
sections of the community.
There is some evidence that non-smokers in urban areas die from cancer of the lung more
frequently than do non-smokers in rural areas but the effect of this on the lung cancer death rate
is much smaller than attributable to tobacco smoking.
7. Conclusions of the Medical Research Council
(a) A very great increase has occurred during the past 25 years in the death rate from lung
cancer in Great Britain and other countries.
(b) A relatively small number of the total cases can be attributed to specific industrial
hazards .
(c) A proportion of cases, the exact extent of which cannot yet be defined, may be due to
atmospheric pollution.
(d) Evidence from many investigations in different countries indicates that a major part of
the increase is associated with tobacco smoking, particularly in the form of cigarettes. In the
opinion of the Council, the most reasonable interpretation of ..his evidence is that the relationship
is one of direct cause and effect.