September 10, 2006
When I was in graduate school, my toxicology professor spent the entire first day lecturing everyone about cigarette smoking. He told us that even if we retained nothing else from his course, he wanted us to remember how deadly smoking is.
He began by explaining that the course would be essentially a study of the metabolism of toxins by various organs in the body. He said, "The human lung is beautifully designed to efficiently take what we breathe and put it into our bloodstream." He added that it also reverses the process, but not always as efficiently. He spoke about some general characteristics of pulmonary anatomy and physiology.
The professor also spoke about the chemicals produced by the incomplete combustion of an organic material like tobacco. While complete combustion breaks down all of the hydrocarbons into water and carbon dioxide, incomplete combustion creates a very wide assortment of compounds with carbon rings. Many of these compounds are highly carcinogenic – such as benzo(a)pyrene – due to the way they fit into the double helix of a DNA strand and break it.
In summary, he explained that when we smoke cigarettes, our lungs place all of those toxic compounds in high doses directly into our bloodstream – whereupon they circulate through our entire bodies. He added, "That is why cigarette smoking is a primary risk factor for all forms of cancer."
Cigarettes in the United States
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Furthermore, cancer is just one of the risks. Cigarette smoking also causes various vascular diseases – especially heart disease and stroke. Emphysema is a particularly gruesome way to end your life, as you slowly suffocate to death.
The International Union Against Cancer (UICC) has a web site filled with comprehensive statistics on deaths from smoking. They used mortality data from the World Health Organization to create summaries for 40 industrialized countries, mostly in Europe.
The results are quite shocking. In the 50 years from 1950 to 2000, "about 63 million people died from smoking" in the industrialized world. That's more people than the entire death toll from World War II. Cigarette smoking is the leading cause of preventable death in the world.
The EPA once listed the top three causes of lung cancer as cigarette smoking, radon gas, and diesel exhaust. Subsequent research revealed that radon is mostly dangerous in homes with cigarette smoke, while it is not a significant risk for people who don't smoke. The radioactive progeny of radon become attached to airborne particles and are inhaled. Higher particle concentrations lead directly to higher radiation doses to the bronchial epithelium.
| UICC Project Leaders and Scientists
Richard Peto, Professor of Medical Statistics, University of Oxford Judith Watt, former Head of Programs, SmokeFree London Jillian Boreham, Senior Research Fellow, University of Oxford Alan Lopez, Professor of Medical Statistics, University of Queensland Michael Thun, Chief of Epidemiology, American Cancer Society |
To further illustrate how toxic cigarettes are, consider a worker in a nuclear weapons lab who has an industrial accident and is exposed to ten times more radiation than the regulations allow (which is already ten times more than natural background from things like radon). If that worker dies of cancer shortly thereafter, and his widow files a wrongful death lawsuit, the case will most likely be thrown out of court if the worker was a lifetime smoker.
Why?
Because the inhaled cigarette tar was far more damaging to the worker's DNA than the radiation – even at such a high level of accidental exposure.