National Cancer Institute NCI Cancer Bulletin: A Trusted Source for Cancer Research News
December 14, 2010 • Volume 7 / Number 24

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Featured Article

New Surgeon General’s Report Outlines How Tobacco Smoke Causes Disease

Surgeon General Dr. Regina M. Benjamin discusses the report at the National Press Club. (Photo courtesy of Christopher Smith) Surgeon General Dr. Regina M. Benjamin discusses the report at the National Press Club. (Photo courtesy of Christopher Smith)

The U.S. Surgeon General, Dr. Regina M. Benjamin, released a report last week describing in detail how tobacco smoke causes disease and death. A compendium of basic research, the 700-page report demonstrates that any exposure to tobacco smoke, either direct or secondhand, causes immediate damage to cells in the body and can lead to disease and death.

“This report makes it clear there is no such thing as a safe cigarette,” said Secretary of Health and Human Services Kathleen Sebelius at a press briefing on December 9. Even brief exposure to secondhand smoke can damage blood vessels and lead to heart problems, including a heart attack. As a nation, she added, “every additional cigarette smoked is making us less healthy.”

The report, How Tobacco Smoke Causes Disease: The Biology and Behavioral Basis for Smoking-Attributable Disease, is the 30th in the series of Surgeon General’s reports on tobacco. The series began with a landmark 1964 report that provided the most rigorous review of the evidence at that time on the hazards of smoking. Subsequent reports focused primarily on which diseases are caused by smoking.

The current report is the first to focus primarily on how smoking-related damage occurs, detailing how nearly every organ in the body is harmed by tobacco smoke, often through similar molecular mechanisms, such as inducing inflammation and oxidative stress.

“It’s important that every American understands what smoking does to their bodies,” Dr. Benjamin said at the briefing. Explaining to the public the science behind the harms of smoking, she continued, could aid efforts to reduce tobacco use. Smokers need to know the biological basis of what happens to their bodies, so that they don’t give up trying to quit, she said, adding that most smokers require multiple quit attempts.

Dr. Benjamin’s mother was a smoker who died of cancer, and her uncle needed help breathing due to emphysema caused by smoking, she recounted. It is never too late to quit, she stressed, and the sooner the better. “Quitting smoking gives your body a chance to heal from the damage caused by cigarettes,” she said.

When a person smokes or inhales secondhand smoke, he or she takes in a complex mixture of more than 7,000 chemicals and compounds, including at least 69 that are known to cause cancer. Every exposure to these cancer-causing chemicals can damage DNA in a way that may lead to cancer. Other chemicals in tobacco smoke can lead to heart disease and chronic lung conditions, such as emphysema.

A graphic illustrating the health consequence of smoking and exposure to secondhand smoke. The health consequences causally linked to smoking and exposure to secondhand smoke (Image from U.S. Department of Health and Human Services 2004, 2006) [Enlarge]

“When you document the damage that smoking does to every organ in the body, the evidence against tobacco becomes overwhelming—it’s pretty scary stuff,” said Dr. David Sidransky, director of the Head and Neck Cancer Research Division at Johns Hopkins University and the report’s lead scientific editor.

“It is the harms that we don’t tend to think about, such as early heart attacks, that are really scary,” he added. The report includes evidence linking sudden infant death syndrome to secondhand smoke exposure. Reproductive effects are also cited, including an increased risk of low birth weight in babies born to mothers who smoke, which increases the risk of infant death.

Research on the biology of addiction is also featured in the report. “These studies show how incredibly complex the biology—and molecular biology—of addiction is,” said Dr. Sidransky. “The only safe answer is to never smoke because you don’t know if, from the perspective of molecular biology, you’re going to become hooked.”

Written for scientists, the report has been summarized in an illustrated booklet using plain language, which Dr. Benjamin said will be translated into Spanish. A one-page summary of the report, including tips for clinicians to help their patients quit, is also available.  

Dr. Benjamin called on clinicians to talk with their patients who smoke about the changes that occur at the cellular and DNA level. “We should give the patients the information and let them make decisions based on the information,” she added.

Studies show that most smokers want to quit and that cessation programs and services can help, explained Assistant Secretary for Health Dr. Howard K. Koh. The national tobacco quitline, 1-800-QUIT-NOW, is one such service. Comprehensive state tobacco control programs and state and local laws that protect the public from exposure to secondhand smoke have also had a significant effect. California has the longest running comprehensive state program, as well as strong smoke-free laws, and rates of lung cancer are declining faster there than in other states, Dr. Benjamin noted.

Even so, smoking remains the leading preventable cause of premature death in the United States and results in more than 440,000 deaths each year. The new report is part of an effort to “renew the national momentum for ending the epidemic,” said Dr. Koh.

The report’s findings are expected to reach a global audience. “Surgeon General’s reports are the scientific basis for tobacco-control efforts in the U.S. and around the world,” said Dr. Cathy Backinger of NCI’s Tobacco Control Research Branch. “This report emphasizes that the best way to reduce your risk for cancer is not to smoke or be exposed to secondhand smoke from others.”

Since the first Surgeon General’s report on tobacco was published in 1964, scientists have continued to develop a deeper understanding of how tobacco smoke causes disease, said Dr. Jonathan Samet of the University of Southern California’s Department of Preventive Medicine and the Norris Comprehensive Cancer Center, who was a contributing editor of the latest report.

Although this information does not change the core message about tobacco, he noted, the findings have implications for trying to better understand, for example, the biology of addiction and whether there are people who are predisposed to addiction. This could lead to more targeted approaches for preventing tobacco-related diseases. “Stay tuned,” he said.

—Edward R. Winstead

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