Does Secondhand Smoke Really Cause Cancer?

Based on the lack of scientific evidence, there is no conclusive data which says secondhand smoke causes cancer.

Over the past few years, the secondhand smoke debate has been discussed and debated endlessly. Here in Ontario Canada, the government just implemented legislation to ban people from smoking in all public places including bars and restaurants.

The new tobacco control legislation, called the Smoke-Free Ontario Act, as well as banning people from smoking in public places, prohibits smokers from smoking at their work place as well.

Similar legislation has also been implemented throughout many parts of United States

There have been dozens of scientific studies linking secondhand to everything from asthma to heart disease. Yet the biggest and most controversial "affect" of secondhand smoke has been its link to cancer.

But is there scientific proof that secondhand smoke actually causes cancer in non-smokers? The short answer, no.

One of the most widely used studies on the effects of secondhand smoke was done by the Environmental Protection Agency (EPA) in a report titled Respiratory Health Effects of Passive Smoke: Lung Cancer and Other Disorders, published in 1992. Based on information at that time, the reported concluded that secondhand smoke is responsible for 3,000 deaths of non smokers each year.

Yet by 1998 a U.S. federal court found that the EPA demonstrated no link between secondhand smoke and cancer. Even more so, the court found that the EPA "...'cherry picked' it's data,' to reach their predetermined conclusion. In other words, they lied.

And yet even after a federal court deemed the report to be complexly wrong, organizations such as the American Cancer Society and the American Lung Association still use the EPA study as their primary source to prove that secondhand smoke causes cancer.

Even on the Health Canada website in a report titled Protection from Second-hand Smoke in Ontario: A Review of Evidence Regarding Best Practices, the main source of "data" comes from the very same EPA study that was thrown out by a federal court. Yet this review was used as proof that secondhand smoke causes cancer and therefor should be banned by stating "all involuntary exposure to tobacco smoke is harmful and should eliminated."

Interestingly, several of the reference links on the Smoke Free Ontario website were either broken, or did not link to the referenced article.

So even with a study which came to a conclusion based on scanty data, and predetermined conclusions, places like Ontario have caved to political and public pressure banning smoking in work and public places to reduce the risk of cancer caused by secondhand smoke.

In a study published in the May 17 2003 issue of the British Medical Journal, researchers found no link between secondhand smoke and lung cancer.

"We found no measurable effect from being exposed to secondhand smoke and an increased risk of heart disease or lung cancer in nonsmokers -- not at any time or at any level," lead researcher James Enstrom, PhD, MPH, of the UCLA School of Public Health, tells WebMD. "The only thing we did find, which was not reported in the study, is that nonsmokers who live with smokers have a increased risk of widowhood because their smoking spouses do die prematurely."

Although the study was "discredited" by many for various reasons, it is still an interesting contrast to previous findings.

In another study published in 1997 by the British Medical Journal titled The accumulated evidence on lung cancer and environmental tobacco smoke, researches concluded that "breathing other people's tobacco smoke is a cause of lung cancer" They reached this conclusion by examining spouses who lived with a smoker over a long period of time and who were "constantly" exposed to secondhand smoke. And in respect to smoking at work the study noted that, "workplace exposure varies considerably and is difficult to measure." So according to this particular study, although a link to secondhand smoke and cancer is significant, there is no data to support wether the amount of secondhand smoke at the workplace is harmful - which is a main issue for the Ontario legislation.

Ultimately most people will agree that smoking is bad for you but so is eating a bucket of fried chicken. The problem is that these reports say that secondhand smoke "causes" cancer.

In an editorial titled Smoking Does Not Cause Lung Cancer, published in the October 1999 issues of the Journal of Theoretics author By: James P. Siepmann, MD said that there are many constituting factors to cancer, but none are responsible for "causing" the disease

"The process of developing cancer is complex and multifactorial. It involves genetics, the immune system, cellular irritation, DNA alteration, dose and duration of exposure, and much more. Some of the known risk factors include genetics asbestos exposure, sex, HIV status, vitamin deficiency, diet pollution , shipbuilding and even just plain old being lazy. When some of these factors are combined they can have a synergistic effect, but none of these risk factors are directly and independently responsible for "causing" lung cancer"

As Siepmann points out in his editorial if these reports said that secondhand smoke "increases the risk of developing cancer" than perhaps that would be a little easier to swallow. But to say that secondhand smoke causes cancer has no concrete scientific merit.

Health Canada even says that they have no idea how much secondhand smoke is considered harmful "No scientific authority or regulatory health body in the world has established a safe level of exposure to second-hand smoke." And yet legislation was still passed.

Many will argue that banning smoking is a threat to our civil liberties. Another serious epidemic in this country and many other parts of the world for that matter is obesity. Should we ban people from eating cake, or asking for a second helping? No, of course not. So why is it ok for the government to tell you where to smoke?

There is little doubt that the 50 are so chemicals found in secondhand smoke are harmful to some degree, but to influence people and create laws based on data which was proven to be inaccurate, is simply too big to ignore.

Perhaps Dr. Siepmann put it best when he said, "We must weigh the risk and benefits of the behavior both as a society and as an individual based on unbiased information. Be warned though, that a society that attempts to remove all risk terminates individual liberty and will ultimately perish. Let us be logical in our endeavors and true in our pursuit of knowledge."