Smoking Out Bad Science

By Lorraine Mooney
Copyright 1998 Dow Jones & Co., Inc.
Wall Street Journal - European Edition (March 12, 1998)

For the past 15 years the anti-smoking lobby has pushed the view that cigarette smoking is a public health hazard. This was a shrewd tactic. For having failed to persuade committed smokers to save themselves, finding proof that passive smoking harmed non-smoking wives, children or workmates meant smoking could be criminalized. Last week the science fell off the campaign wagon when the definitive study on passive smoking, sponsored by the World Health Organization, reported no cancer risk at all.

But don't bet that will change the crusaders' minds. smoking, like fox hunting, is something that certain factions want to ban simply because they don't like it. It has slipped from a health crusade to a moral one. Today, National No smoking Day in Britain will be marked by demagoguery from the Department of Health, which has already set its agenda to ban smoking. The U.K. Scientific Committee on Tobacco or Health (SCOTH) report on passive smoking, due out Thursday, is headed by a known anti-tobacco crusader, Professor Nicholas Wald of the Royal London School of Medicine.

However, it is now obvious that the health hazard of environmental tobacco smoke (ETS) has been knowingly overstated. The only large-scale definitive study on ETS was designed in 1988 by a WHO subgroup called the International Agency on Research on Cancer (IARC). It compared 650 lung-cancer patients with 1,542 healthy people in seven European countries. The results were expressed as "risk ratios," where the normal risk for a non-smoker of contracting lung cancer is set at one. Exposure to tobacco smoke in the home raised the risk to 1.16 and to smoke in the workplace to 1.17. This supposedly represents a 16% or 17% increase. But the admitted margin of error is so wide--0.93 to 1.44--that the true risk ratio could be less than one, making second-hand smoke a health benefit.

This is what anyone with common sense might have expected. After all, the dose makes the poison. But in 1988, IARC decreed mainstream tobacco smoke as a carcinogen, fully expecting that the second-hand product would have a similar, lower effect which would be capable of measurement by linear extrapolation. In anticipation of confirmation of this belief many countries have been adopting anti-smoking policies in the name of public health. The U.S. Environmental Protection Agency has confidently stated that 3,000 Americans die annually from inhaling environmental tobacco smoke, and the state of California leads the pack with a total smoking ban in all public places enacted on Jan. 1, 1998. Although Iran did enact such a ban in 1996, this was overturned as unconstitutional. The Indian city of Delhi has a smoking ban and Britain is working toward one.

Before the IARC study, no other reliable study on ETS was available. For the effect of the modestly increased risk of ETS to be detected, the number of cases in the study must be very high in order to distinguish the effect from other background noise. Acting in the most unscientific manner, the U.S. EPA decided to pool results of 11 studies, 10 of which were individually non- significant, to arrive at a risk ratio of 1.19. As is always a problem with this kind of meta-analysis, the studies were all different from each other in various ways so that they were not measuring the same thing.

Last October, the British Medical Journal ran the results of a similarly flawed study by SCOTH's Mr. Wald claiming an increased risk of lung cancer from ETS of 26%. It was supported by an editorial and timed to coincide with noise from the anti-smoking lobby and a Department of Health press release, talking of "shocking" figures and alluding to innocent victims. The Wald report has been dismissed as a "statistical trick" by Robert Nilsson, a senior toxicologist at the Swedish National Chemicals Inspectorate and a professor of toxicology at Stockholm University. He says that there are so many unacknowledged biases in Mr. Wald's analysis that the alleged risk figure is meaningless. For example, Mr. Wald relies on data from the memories of spouses as to how much their dead partner used to smoke. Survey bias is often considerable, potentially far higher than the 26% estimate of increased risk, but this is not even mentioned by the authors. Mr. Nilsson also explains that Mr. Wald's meta-analysis has pooled data from non-comparable studies. His most stinging criticism is aimed at the BMJ editorial board, who he considers must be "innocent of epidemiology" to have allowed publication of the Wald paper in its existing form. Nevertheless the U.K. SCOTH inquiry into ETS due to report on Thursday, with Mr. Wald at the helm, will probably ignore the flaws of the Wald study and brand ETS a killer.

New Labour has done a U-turn on fox hunting. Will it do one on Thursday when SCOTH reports? Or will it ignore the best evidence and press on with public smoking bans? My guess is that two climbdowns in a month is one too many. It will remind us all this week that smoking is bad for you and eventually ban it in public.

Ms. Mooney is medical demographer for the Cambridge-based European Science and Environment Forum.

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