THE WALL STREET JOURNAL
Smoking Out Bad Science

By Lorraine Mooney

For the past 15 years the antismoking lobby has pushed the view that second hand cigarette smoke is a public health hazard. This was a shrewd tactic. For, having failed to persuade the most committed smokers to save themselves, they could use proof that passive smoking harms non smoking wives, children and co-workers to make the case for crimin- alizing smoking.

But the science fell off the campaign wagon two weeks ago when the definitive study on passive smoking, sponsored by the World Health Organization, reported no cancer risk at all. Don't bet that will change the crusaders' minds. The anti-smoking movement after all, has slipped from a health crusade to a moral one.

It is now obvious that anti-smoking activists have knowingly overstated the health risk of second hand smoke. The only definitive large- scale study on the subject was designed in 1988 by a WHO subgroup called the International Agency on Research on Cancer. 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 nonsmoker of contracting lung cancer is set as 1. Exposure to tobacco smoke in the home raised the risk to 1.16, and exposure to smoke in the workplace increased it 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 trivial or nonexistent.

This is what anyone with common sense might have expected. After all, the dose makes the poison, and a pack-a-day smoker is exposed to a lot more smoke than his wife or office mate. Nonetheless in 1988, the International Agency on Research on Cancer decreed tobacco smoke a carcinogen, fully expecting that the secondhand product would have a similar, lower effect that could be extrapolated from what we know about the risk to smokers.

Anticipating that science would confirm this hypothesis, many countries have been adopting antismoking policies in the name of public health. The U.S. Environmental Protection Agency has confidently stated that 3,000 Americans die annually from inhaling second hand tobacco smoke. The state of California has imposed a total smoking ban in all public places, which took effect on Jan. 1. California is not the first jurisdiction to enact such a ban: Iran did so in 1996- but it was overturned as unconstitutional.

Before the International Agency on Research on Cancer Study, no other reliable study on second hand smoke was available. In trying to detect such a modest increase, the margin of error is very high, which means the number of cases in the study must be very high. Acting in the most unscientific manner, The EPA decided to pool the results of 11 studies, 10 of which found no statistically significant risk, 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 published the results of a similarly flawed study by a known antitobacco crusader, Nicholas Wald, who heads Britain's Scientific Committee on Tobacco and Health. Mr. Wald's study claimed a 26% increase in the risk of lung cancer from secondhand smoke. The study was accompanied by an editorial that described the findings as "shocking".

But Robert Nilsson, a senior toxicologist at the Swedish National Chemicals Inspect- orate and a professor of toxicology at Stockholm University, has dismissed the study as a "statistical trick." He says there are so many unacknowledged biases in the analysis that the alleged risk figure is meaningless. For example, Mr. Wald relies on the memories of widows and widowers as to how much their dead spouses used to smoke. Survey bias is often considerable, potentially far higher than 26% estimate of increased risk, a fact the Wald report doesn't even mention.

Mr. Nilsson also explains that Mr. Wald's meta-analysis has pooled data from incomparable studies. His most stinging criticism is aimed at the British Medical Journal's editorial board members, who he says must be "innocent of of epidemiology" to have allowed publication of the paper in its existing form.

Nevertheless, Britain's chief medical officer, Sir Kenneth Kalman, said last week that the Wald report established a "definitive link" between second hand smoke and cancer, which the Labor government will use in developing antismoking proposals. Science notwithstanding, antitobacco hysteria is alive and well on both sides of the Atlantic. Ms. Mooney is a medical demographer for the Cambridge based European Science and Environment Forum.