Tobacco and Public Health - TCSC Indonesia

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THE GREAT STUDIES OF SMOKING AND DISEASE IN THE TWENTIETH CENTURY
heavy cigarette smokers in the British Doctors Study (Doll and Hill 1956). While the
relative risk (RR) estimates were lower for death from laryngeal cancer (RR = 5.4) and
chronic bronchitis (RR = 6.1) than for lung cancer, they nevertheless persuaded the
1964 Advisory Committee to conclude that cigarette smoking caused lung cancer,
laryngeal cancer, and chronic bronchitis in men (US Public Health Service 1964).
Early consensus groups were more cautious in interpreting the relationship of smoking
with various cardiovascular diseases and other conditions. The 1964 Report to the
Surgeon General noted that ‘Male cigarette smokers have a higher death rate from
coronary artery disease than non-smoking males, but it is not clear that the association
has causal significance’ (RR = 6.1) (US Public Health Service 1964). The median relative
risk for death from coronary heart disease in male smokers compared to nonsmokers
was 1.7 (range 1.5–2.0) in the cohort studies reviewed in 1964. However, by
1967 a later Surgeon General Report concluded, ‘The convergence of many types of evidence—epidemiological,
experimental, pathological, and clinical—strongly suggests
that cigarette smoking can cause death from coronary heart disease’ (US Public Health
Service 1967). The language attributing causation became progressively stronger over
time, as results from the Framingham Study and other cardiovascular cohorts
confirmed that smoking, hypertension, and increased cholesterol were all strong and
independent risk factors (Kannell et al. 1966).
With prolonged follow-up, the cohort studies included many more cases and/or
deaths from less common conditions, and more detailed analyses of diseases attributable
to smoking. By 1989, the US Surgeon General had designated 14 disease categories
that contribute to smoking-attributable deaths in the United States (US Department of
Health and Human Services 1989). These included coronary heart disease; hypertensive
heart disease; cerebrovascular lesions; aortic aneurism (non-syphilitic); ulcer (gastric,
duodenal, jejeunal); influenza and pneumonia; bronchitis and emphysema; and
cancers of the lip, oral cavity, and pharynx, esophagus, pancreas, larynx, lung, kidney,
and bladder and other urinary organs (US Department of Health and Human Services
1989). An updated review by the International Agency for Research on Cancer (IARC)
in 2002 refined this list by including cancers of the naso-, oro-, and hypopharynx, nasal
cavity, paranasal sinuses, stomach, liver, kidney (parenchyma as well as renal pelvis),
ureter, uterine cervix, and bone marrow (myeloid leukemia) (IARC 2002).
Besides contributing to the inventory of diseases officially designated as caused by
smoking, the cohort studies also reveal how the epidemic changed, and evolved, over
time. This progression is particularly evident in the increase in lung cancer death rates
that occurred among women smokers in the two American Cancer Society cohorts,
during the past 50 years (Garfinkel and Stellman 1988; Thun et al. 1997), and in the
growing disparity in overall survival rates between smokers and non-smokers from the
first to the second half of the British Doctors Study (Doll et al. 1994, 2000).
Figure 2.1 illustrates the death rate from lung cancer among women who smoked
cigarettes, within 5-year age intervals, for four time periods between 1960 and 1986.