Tobacco and Public Health - TCSC Indonesia

288
PASSIVE SMOKING AND HEALTH
organs, coronary heart disease, and ‘emphysema and chronic bronchitis,’ now termed
chronic obstructive pulmonary disease (COPD). The studies were observational, that
is comparing risks of disease in those who smoked with those who did not, and were
primarily of the cohort (following smokers and nonsmokers and measuring the rate at
which disease develops in the two groups) and case-control (designs comparing rates
of smoking in persons with the disease under study and in controls who are similar but
do not have the disease). Surveys, or cross-sectional studies, were also carried out,
particularly to compare rates of lung disease in smokers and nonsmokers. These same
designs were subsequently used to investigate the risks of passive smoking.
By the 1960s, there was strong evidence that active smoking was a powerful cause of
disease. For example, the risk of lung cancer in men who smoked was increased 10-fold
or more compared to men who had never smoked, and the risk increased with the
number of cigarettes smoked and the duration of smoking (US Department of Health
Education and Welfare 1964). These initial observations quickly sparked complementary
laboratory studies on the mechanisms by which tobacco smoking causes disease.
The multidisciplinary approach to research on tobacco has been key in linking active
and passive smoking to various diseases; the observational evidence has been supported
with an understanding of the mechanisms by which smoking causes disease.
By 1953, for example, Wynder and colleagues (1953) had shown that painting the skin
of mice with the condensate of cigarette smoke caused tumors. In combination with
the emerging epidemiologic evidence on smoking and lung cancer, this observation
was sufficiently powerful to be followed by the US tobacco industry’s dramatic
response of establishing the Tobacco Industry Research Committee, later to become
the Tobacco Research Council, and to initiate a campaign to discredit the emerging
scientific evidence. This same tactic is still being used by the tobacco industry for
research on passive smoking.
By the late 1950s and early 1960s, the mounting evidence on active smoking received
formal review and evaluation by government committees, leading to definitive conclusions
on causation in the early 1960s. In the United Kingdom, the 1962 report of the
Royal College of Physicians (Royal College of Physicians of London 1962) concluded
that smoking was a cause of lung cancer and bronchitis and a contributing factor to
coronary heart disease. In the United States, the 1964 report of the Advisory Committee
to the Surgeon General concluded that smoking was a cause of lung cancer in men and
of chronic bronchitis (US Department of Health Education and Welfare 1964). This
conclusion was based in a systematic and comprehensive evaluation of evidence and
application of criteria for judgment as to the causality of association. The criteria
included the association’s consistency, strength, specificity, temporal relationship, and
coherence. By law, a U.S. Surgeon General’s report was subsequently required annually
and new conclusions have been reached periodically with regard to the diseases caused
by smoking. The Royal College of Physicians has also continued to release periodic
reports, as have other organizations. These reports and other expert syntheses of the