August 01, 2006
4 min read

Exposure to secondhand smoke places general public at severe health risk

The health effects of secondhand smoke exposure are more pervasive than experts previously thought.

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There is no risk-free level of exposure to secondhand smoke, according to a comprehensive scientific report issued by Surgeon General Richard H. Carmona, MD, MPH, FACS.

Nonsmokers exposed to secondhand smoke at home or work increase their risk of developing heart disease by 25% to 30% and lung cancer by 20% to 30%. The finding is a major public health concern because nearly half of all nonsmokers are still regularly exposed to secondhand smoke.

The report, The Health Consequences of Involuntary Exposure to Tobacco Smoke, states that even brief secondhand smoke exposure can cause immediate harm. The only way to protect nonsmokers from the dangerous chemicals in secondhand smoke is to eliminate smoking indoors, according to the report.

History of exposure

In 1964, the first Surgeon General’s report identified active smoking as a cause of lung cancer. Since then, researchers have identified more than 50 carcinogenic compounds and many other toxic substances in tobacco smoke, according to Carmona who added that smoking tobacco is acknowledged as the leading cause of lung cancer.

Secondhand smoke exposure at home or work increases nonsmokers’ risk of heart disease by 25% to 30% and lung cancer by 20% to 30%.

In 1981, the first major epidemiologic studies of secondhand smoke and lung cancer revealed that nonsmoking women married to smokers had a higher risk of lung cancer than did nonsmoking women married to nonsmokers. Thereafter, in numerous studies, researchers continued to confirm a causal relationship between secondhand smoke exposure and lung cancer. In 1986, the Surgeon General concluded that secondhand smoke indeed poses a risk for nonsmokers.

“Because the compounds that are inhaled by the active smoker are also present in the mixture of sidestream and exhaled mainstream smoke inhaled by involuntary smokers, it is biologically plausible that secondhand smoke is also a cause of lung cancer among nonsmokers,” he wrote in a report.

Health hazards

“The report is a crucial warning sign to nonsmokers and smokers alike,” said Health and Human Services Secretary Michael Leavitt in a prepared statement. “Smoking can sicken and kill, and even people who do not smoke can be harmed by smoke from those who do.”

Secondhand smoke exposure can cause heart disease and lung cancer in nonsmoking adults and is a known cause of sudden infant death syndrome, respiratory problems, ear infections, and asthma attacks in infants and children, according to the report.

“The health effects of secondhand smoke exposure are more pervasive than we previously thought,” said Carmona, vice admiral of the Public Health Service, in a prepared statement. “The scientific evidence is now indisputable: secondhand smoke is not a mere annoyance. It is a serious health hazard that can lead to disease and premature death in children and nonsmoking adults.”

Secondhand smoke contains more than 50 cancer-causing chemicals and is a known human carcinogen. Nonsmokers who are exposed to secondhand smoke inhale many of the same toxins as smokers. Even brief exposure to secondhand smoke has immediate adverse effects on the cardiovascular system and increases risk for heart disease and lung cancer, according to the report. Infants and children are especially vulnerable to the poisons in secondhand smoke because their bodies are still developing.

“The U.S. Surgeon General’s new report confirms what we already knew: that passive smoking kills,” said Janet Voûte, MA, chief executive officer of the World Heart Federation, in a prepared statement. “Nonsmokers who breathe secondhand smoke have a significantly greater risk of cardiovascular diseases, including heart attacks and strokes, as well as various grave respiratory diseases and cancers.”

Preventing exposure

“The report’s finding that ‘there is no risk-free level of exposure to secondhand smoke’ is entirely consistent with the World Health Organization Framework Convention on Tobacco Control, which states, ‘Scientific evidence has unequivocally established that exposure to tobacco smoke causes death, disease and disability,’” said Voûte.

According to the report, even the most sophisticated ventilation systems cannot completely eliminate secondhand smoke exposure and only smoke-free environments afford full protection

“The good news is that, unlike some public health hazards, secondhand smoke exposure is easily prevented,” said Carmona. “Smoke-free indoor environments are proven, simple approaches that prevent exposure and harm.”

Making progress

Carmona noted that levels of cotinine, a biological marker for secondhand smoke exposure, measured in nonsmokers have decreased by 70% since the late 1980s. The proportion of nonsmokers with detectable cotinine levels has reduced by half from 88% in 1988 through 1991 to 43% in 2001 through 2002.

“Our progress over the past 20 years in clearing the air of tobacco smoke is a major public health success story,” Carmona said. “We have averted many thousands of cases of disease and early death and saved millions of dollars in health care costs.”

The only way to protect nonsmokers from the dangerous chemicals in secondhand smoke is to eliminate smoking indoors.

Carmona said that sustained efforts are required to protect the more than 126 million Americans who continue to be regularly exposed to secondhand smoke in the home, at work and in enclosed public spaces.

To help publicize the report’s findings, Carmona released an easy-to-read guide with practical information on the dangers of secondhand smoke and steps people can take to protect themselves.

Tobacco control convention

“Countries should use the report as further incentive to protect the rights of nonsmokers, as called for in the convention, by banning smoking in indoor workplaces, indoor public places and public transport,” said Voûte.

“Although the convention took effect in February 2005, not all countries abide by its terms,” she said. “Countries that have not signed should sign. Countries like the United States that have signed but not ratified should ratify. And countries that have both signed and ratified should fully meet their binding commitments.”

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