U.S. Surgeon General Richard Carmona said on June 27, “The debate is over. The science is clear: Secondhand smoke is not a mere annoyance, but a serious health hazard.”
Most people can be forgiven for having thought the truth lay somewhere in between: Working in a smoke-filled bar for 20 years seems likely to pose a risk to your health, but our bodies can probably tolerate occasional exposure to cigarette smoke.
Secondhand smoke is a dramatically diluted substance compared to what active smokers breathe in. Spending an hour in a typical bar back in the 1970s was the equivalent of smoking only .004 cigarettes. The level of smoke contaminants in today’s bars is much lower, and several orders of magnitude less than OSHA indoor air quality standards.
In toxicology they say “the dose makes the poison.” Tiny amounts of seemingly toxic compounds are often harmless or (like vitamins) even essential for good health. Large amounts of seemingly benign substances (like salt or even water) are often deadly. The case against secondhand smoke has always foundered on this basic rule of science.
If the toxicological case against secondhand smoke seems dubious, the epidemiological case is weaker still. Epidemiology is the science of diseases in groups of people. Researchers have looked at the health of spouses and children of smokers for evidence of secondhand smoke’s effects. The most comprehensive study of this type was published in 2003 in the British Medical Journal. It found “no causal relationship between exposure to ETS [environmental tobacco smoke] and tobacco-related mortality.”
Even smaller and less well-controlled studies typically do not find negative effects of secondhand smoke, and those that do find relative risks too small to rule out the possibility that they are the result of pure chance. So small and uncertain is the effect that some studies, such as a major one undertaken by the World Health Organization, even seem to find a positive effect on the health of smokers’ children.
A new report from the Surgeon General claims otherwise. “Secondhand smoke is a major cause of disease, including lung cancer and coronary heart disease, in healthy nonsmokers,” it reads. “In 2005, it was estimated that exposure to secondhand smoke kills more than 3,000 adult nonsmokers from lung cancer, approximately 46,000 from coronary heart disease, and an estimated 430 newborns from sudden infant death syndrome.”
The Surgeon General’s report is a massive tome, some 727 pages, and the list of doctors and public health experts who contributed to it runs page after page. How can anyone claim they are all wrong? Why would they lie?
The short answer is: They are not lying. The longer answer is that doctors and scientists are just as susceptible as the rest of us to groupthink, clinging to obsolete paradigms, and confusing self-interest with principles.
The notion that researchers can start with the observed effects of massive doses of a chemical on laboratory animals and accurately project the number of human deaths caused by exposure that is orders of magnitude less is a flawed paradigm that survives despite devastating criticism in the peer-reviewed literature.
The anti-smoking movement has become a well-funded industry, with funding flowing in from government grants, foundations, and corporations that sell smoking cessation aides. Billions of dollars are being spent to discourage and ban smoking.
People being paid to demonize tobacco products and their users may not be the best judges of whether the scientific debate is settled. Forgive me for believing that what General Carmona says is an accurate expression of the politics and passions of the moment, but not necessarily of the real science of the health effects of secondhand smoke.
Joseph Bast ([email protected]) is president of The Heartland Institute and author of a new book about smoking, Please Don’t Poop in My Salad.