The WHO research findings put pressure on the Government to ban smoking in
Passive smoking does cause lung cancer, a scientific working group of the
World Health Organisation has concluded.
The finding has added to pressure on the Government to force employers to
ban or severely restrict smoking in workplaces, a move it stepped back from
imposing last summer.
The WHO study, by the International Agency for Research on Cancer, reviewed
all the significant published evidence related to tobacco smoking and cancer.
Its conclusions confirmed that active smoking can cause cancer, backing the
findings of a 1986 working party, but also that second-hand smoke should be
classified as carcinogenic to humans.
One half of all persistent cigarette smokers were eventually killed by
tobacco-caused diseases, with half the deaths occurring between the ages of 35
The average life expectancy of an active smoker was 20 years less than a
non-smoker, it added.
Smoking among females in developing countries was "an emerging
epidemic" and smoking caused even more deaths from cardiovascular, lung
disease and strokes than it did from cancer.
Smoking caused more types of cancer than previously thought, including
cancers of the stomach, liver, uterus, cervix and kidney and myeloid leukaemia.
And the risks of cancer increased the longer someone smoked.
"Most of the harmful effect is avoided if smoking is stopped in the
early 30s, but reduction in risk is obtained even when smoking is stopped later
in life," the working party said.
In the US and UK, roughly 90 per cent of lung cancers in both men and women
were attributable to cigarette smoking.
Non-smokers were exposed to the same carcinogens as active smokers, it
added. "Even the typical levels of passive exposure have been shown to
cause lung cancer among non-smokers. Second-hand tobacco smoke is carcinogenic
to humans," it concluded.
After pressure from pubs and restaurants, the Government last year rejected advice
from the Health and Safety Commission for a code to force employers either to
ban smoking or take stringent measures to protect staff from others’ smoke.