A number of studies
funded by the tobacco industry have yielded results inconsistent
with the scientific consensus, or have criticised the
epidemiological approach associated with that consensus.
A 2003 study by Enstrom and Kabat, published in the British
Medical Journal, argued that the harms of passive smoking had
been overstated. Their analysis reported no statistically
significant relationship between passive smoking and lung
cancer, though the accompanying editorial noted that "they may
overemphasise the negative nature of their findings." This paper
was widely promoted by the tobacco industry as evidence that the
harms of passive smoking were unproven. The American Cancer
Society (ACS), whose database Enstrom and Kabat used to compile
their data, criticized the paper as "neither reliable nor
independent", stating that scientists at the ACS had repeatedly
pointed out serious flaws in Enstrom and Kabat' s methodology
prior to publication. Enstrom's ties to the tobacco industry
also drew scrutiny; in a 1997 letter to Philip Morris, Enstrom
requested a "substantial research commitment... in order for me
to effectively compete against the large mountain of
epidemiologic data and opinions that already exist regarding the
health effects of ETS and active smoking." The study was funded
and managed by the Center for Indoor Air Research, a tobacco
industry front group, and Enstrom's work was viewed by Philip
Morris as "clearly litigation-oriented." Enstrom himself has
defended the accuracy of his study against what he terms
"illegitimate criticism by those who have attempted to suppress
and discredit it.
Gio Batta Gori, a tobacco industry consultant and spokeperson,
wrote in the libertarian Cato Institute's journal Regulation
that "...of the 75 published studies of ETS and lung cancer,
some 70 percent did not report statistically significant
differences of risk and are moot. Roughly 17 percent claim an
increased risk and 13 percent imply a reduction of risk."[108]
Steven Milloy, the "junk science" commentator for Fox News and a
former Philip Morris consultant, claimed that "...of the 37
studies [on passive smoking], only 7 – less than 19 percent –
reported statistically significant increases in lung cancer
incidence."
Another component of criticism promoted by Milloy focused on
relative risk and epidemiological practices in studies of
passive smoking. Milloy argued that studies yielding relative
risks of less than 2 were meaningless junk science. This
approach to epidemiological analysis was criticized in the
American Journal of Public Health:
A major component of the industry attack was the mounting of a
campaign to establish a "bar" for "sound science" that could not
be fully met by most individual investigations, leaving studies
that did not meet the criteria to be dismissed as "junk
science."
The tobacco industry and affiliated scientists also put forward
a set of "Good Epidemiology Practices" which would have the
practical effect of obscuring the link between secondhand smoke
and lung cancer; the privately-stated goal of these standards
was to "impede adverse legislation". However, this effort was
largely abandoned when it became clear that no independent
epidemiological organization would agree to the standards
proposed by Philip Morris et al.
Controversy over harms of passive smoking World Health
Organization controversy >>
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Second Hand Smoke Passive smoking
Long-term
effects
Short-term
effects
Causal
mechanisms
Epidemiological studies of passive smoking
1. Studies of passive smoking in animals
2.
Risk level of passive smoking
Current state of scientific opinion
1. Public
opinion
Controversy over harms of passive smoking
1. Critique of individual studies and epidemiology
2. World Health Organization controversy
3. EPA lawsuit
4. Tobacco-industry funding of research
Tobacco industry response
1. Position of major tobacco companies
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