Tobacco and Public Health - TCSC Indonesia

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TOBACCO AND CARDIOVASCULAR DISEASE
Table 32.2 Application of Bradford Hill criteria to the evidence on ACTIVE smoking and
arterial disease
Criterion Manifestation of arterial disease
Ischaemic Cerebrovascular Abdominal Peripheral
heart disease disease aortic aneurysm arterial disease
Strength ✓ ✓ ✓ ✓
dose–response ✓ ✓ ✓ ✓
Consistency
time ✓ ✓ ✓ ✓
place ✓ ✓ ✓ ✓
person ✓ ✓ ✓ ✓
epidemiological method ✓ ✓ � ✓
Temporal sequence ✓ ✓ � ✓
Reversibility
individual ✓ ✓ � �
population ✓ � � �
Specificity � � � �
Biological plausibility ✓ ✓ ✓ ✓
✓ = Evidence available and supports criterion.
� = Available evidence does not support criterion.
� = Evidence either not available or inconclusive.
of secular trends in these diseases in whole communities, and the role that changes in
smoking habits play in initiating and maintaining those trends, is even more difficult.
Secondly, as the foregoing discussion makes clear, smoking is just one of several major,
independent, and potentially modifiable risk factors for development of CVD, which
has direct implications for Bradford Hill’s criterion of specificity. Thirdly, if both cigarettes
and patterns of their use change simultaneously, it may be close to impossible
to discern, at least retrospectively, how much, if any, each change contributed to a
population’s experience of CVD.
But all of this is to run before we can walk. Let us first consider the individual criteria
proposed by Bradford Hill and how they apply to the data on active smoking. Table 32.2
summarizes such a survey.
Strength and dose–response
As may be seen from Table 32.2, active smoking of cigarettes is a strong risk factor for
disease in each of the four principal arterial territories, and shows an obvious
dose–response in each. The dose–response relationships shown in Tables 32.3 and 32.4
are representative of those seen internationally, and those for IHD in Perth are further
supported by data from cohort studies conducted in the same population (see Table 32.5).
Unexpectedly, follow-up of healthy subjects recruited to the earlier case–control study