The news media have parroted the idea that secondhand smoke is harmful, and a recent survey finds that more than 80 percent of adults now believe this. But the secondhand-smoke scare is based largely on speculation reminiscent of superstitions from the Middle Ages, before the discovery of the scientific method.
The 2006 surgeon general's 709-page report "The Health Consequences of Involuntary Exposure to Tobacco Smoke" further promotes this sham. The report claims that even brief exposure to secondhand smoke can cause immediate harm and cites reports that estimate secondhand smoke causes approximately 3,000 lung cancer deaths and tens of thousands of heart disease deaths among nonsmokers each year.
It concludes that there is no risk-free level of exposure, and recommends "smoke-free policies" to eliminate all indoor smoking. Surgeon General Richard Carmona himself stated at a June 27, 2006, press conference, "The science is clear: [secondhand smoke] is a serious health hazard that causes premature death and disease in children and non-smoking adults."
The Environmental Protection Agency, American Lung Association, American Public Health Association, and American Cancer Society all concur. The California Air Pollution Authority has labeled secondhand smoke a toxin and the EPA has initiated a "Smoke-Free Home Pledge Campaign."
Marriott has announced that its 2,300 hotels will become totally smoke-free by October 15 of this year. In June, a California state Senate committee approved a bill to ban smoking in private cars with children.
But the science is not "clear." In fact, there is no credible scientific evidence to support any of this. Whereas the association of cigarette smoking with heart disease and lung cancer in epidemiologic studies is strong--an increase of 100 to 300 percent and 900 percent respectively--the association found between secondhand-smoke exposure and heart disease and lung cancer in the studies cited by the surgeon general is very weak, an increase of about 30 percent for each.
In addition, the report cherry-picks studies that support its claims and ignores other important ones that do not. For example, it cites a 1993 EPA meta-analysis of 30 studies, that has since been discredited, and ignores an excellent 1998 World Health Organization large single study that showed a reduced association for children of smokers and no association for spouses and co-workers.
The largest single study of all, a 39-year analysis of over 35,000 Californians published in 2003 in the British Medical Journal, found no connection between passive smoking and mortality. It was not cited.
Epidemiology is the study of disease in populations. Epidemiologists collect data using poorly controlled observational studies and evaluate it by using statistical methods.
These methods are not adequate to test the hypotheses required by the scientific method, so epidemiology can never prove or disprove anything. It uses "relative risk" to report its findings of association. An RR of 1.0 is average, while an RR of 3.0 or more--a 300 percent increase--is required to suggest causation.
The epidemiologic studies cited by the surgeon general's report cannot determine causation largely because they are unable to control for inherent systematic errors. These include measurement errors, confounding factors, and at least 56 different biases, including "recall bias."
In the studies cited by the surgeon general, not only do the researchers have no control over the exposures to secondhand smoke, they don't even know what the data are.
A weak association is a fortuitous finding. Converting it into a causal link bypasses the scientific method, and has been termed "statistical malpractice" in the literature.
This unethical application of statistics to the imperatives of health policy is a common occurrence in politically motivated science.
The report claims that the weak statistical associations found in the studies "were not determinant" in making causal inferences, but instead, "judgments were based on an array of considerations." What these considerations were, and why they were more important than the results of the studies cited, is not apparent.
Finally, a basic principle of toxicology is that "the dose makes the poison." The surgeon general's report admits that secondhand smoke "is rapidly diluted as it travels away from the burning cigarette," and that it cannot be defined or measured.
It takes many years of persistent exposure for cigarette smoking to cause disease. For example, a patient's smoking one pack of cigarettes (22 cigarettes) a day for 10 years alerts a physician to search for lung disease. But even in the smokiest of smoke-filled rooms, nonsmokers inhale only a fraction of one cigarette a day.
To be beneficial, public policy must be based on good science. Bad science inevitably leads to bad public policy.
All government bureaucracies have one hidden agenda--to increase their funding and power. This leads to misrepresentations like the secondhand-smoke scare.
The 2006 surgeon general's report reminds us that one ongoing peril for citizens is being misled by government bureaucrats seeking to expand their power.
We need to shape our policies on the basis of good science, instead of shaping the science to fit the policies.