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Secondhand Tobacco Smoke: Review the Facts
Secondhand Smoke is Harmful to All People1
Secondhand smoke is a health hazard for all people: it is harmful to both children and adults, and to both women and men. It is harmful to nonsmokers whether they are exposed in their homes, their vehicles, their workplaces, or in enclosed public places. We have found that certain populations are especially susceptible to the health effects of secondhand smoke, including infants and children, pregnant women, older persons, and persons with pre-existing respiratory conditions and heart disease.
It is not surprising that secondhand smoke is so harmful. Nonsmokers who are exposed to secondhand smoke inhale the same toxins and cancer-causing substances as smokers. Secondhand smoke has been found to contain more than 50 carcinogens and at least 250 chemicals that are known to be toxic or carcinogenic. This helps explain why nonsmokers who are exposed to secondhand smoke develop some of the same diseases that smokers do.
Health Effects of Exposure to Secondhand Smoke in Adults
Let’s look first at the health effects that secondhand smoke causes in adults.
Lung Cancer
The Report confirms that secondhand smoke is a known human carcinogen that causes lung cancer in nonsmoking adults. Nonsmokers who are exposed to secondhand smoke, at home or at work, increase their risk of developing lung cancer by 20 percent to 30 percent. Secondhand smoke causes approximately 3,000 lung cancer deaths among U.S. nonsmokers each year.
Heart Disease
The Report released today also concludes that secondhand smoke causes heart disease. Nonsmoking adults who are exposed to secondhand smoke at home or at work increase their risk of developing heart disease by 25 to 30 percent. The evidence indicates that even brief secondhand smoke exposures can have immediate adverse effects on the cardiovascular system. This is especially true for persons who already have heart disease, or who are at special risk of heart disease. Secondhand smoke causes tens of thousands of heart disease deaths each year among U.S. nonsmokers.
Health Effects of Secondhand Smoke Exposure in Children
Now let’s turn to the special health risks that secondhand smoke poses to children. Because their bodies are still developing, infants and children are especially vulnerable to the poisons in secondhand smoke.
Respiratory Infections
Secondhand smoke is a cause of respiratory conditions in children - we’ve known that since our study of second hand smoke effects began in 1986. However, after further research and analysis, we have found that the consequences of smoke on a child’s respiratory system are more severe than originally thought. Acute respiratory infections such as bronchitis and pneumonia, respiratory symptoms such as cough, phlegm, wheezing, and breathlessness, more frequent and severe asthma attacks, slowing of lung growth, and ear infections have all been proven to be results of exposure to secondhand smoke in children.
SIDS
We have determined that secondhand smoke is a cause of sudden infant death syndrome (SIDS). Infants who die from SIDS tend to have higher concentration of nicotine in their lungs and higher levels of cotinine (a biological marker for secondhand smoke exposure) than infants who die from other causes. We have also found that infants who are exposed to secondhand smoke after birth are also at increased risk of dying of SIDS.
In addition, babies of nonsmoking women who are exposed to secondhand smoke during pregnancy are at risk for a small reduction in birth weight. Chemicals in secondhand smoke appear to affect the brain in ways that interfere with its regulation of infants’ breathing.
There is No Risk-Free Level of Exposure to Secondhand Smoke
We know that secondhand smoke harms people’s health, but many people assume that exposure to secondhand smoke in small doses does not do any significant damage to one’s health. However, science has proven that there is NO risk-free level of exposure to secondhand smoke. Let me say that again: there is no safe level of exposure to secondhand smoke.
Breathing secondhand smoke for even a short time can damage cells and set the cancer process in motion. Brief exposure can have immediate harmful effects on blood and blood vessels, potentially increasing the risk of a heart attack. Secondhand smoke exposure can quickly irritate the lungs, or trigger an asthma attack. For some people, these rapid effects can be life-threatening. People who already have heart disease or respiratory conditions are at especially high risk.
Establishing Smoke-free Environments is the Only Proven Way to Prevent Exposure
The good news is that, unlike some public health hazards, secondhand smoke exposure is preventable. A proven method exists for protecting nonsmokers from the health risks associated with secondhand smoke exposure: avoiding places where secondhand smoke is present.
Smoke-free environments are the ONLY approach that effectively protects nonsmokers from the dangers of secondhand smoke. The simple separation of smokers and nonsmokers within the same air space may reduce, but does not eliminate, secondhand smoke exposure among nonsmokers. The current Report expands on that finding by concluding that even sophisticated ventilation approaches cannot completely remove secondhand smoke from an indoor space. Because there is no risk-free level of secondhand smoke exposure, anything less cannot ensure that nonsmokers are fully protected from the dangers of exposure to secondhand smoke.
According to the EPA2, in children:
- ETS (Environmental Tobacco Smoke) exposure increases the risk of lower respiratory tract infections such as bronchitis and pneumonia. EPA estimates that between 150,000 and 300,000 of these cases annually in infants and young children up to 18 months of age are attributable to exposure to ETS. Of these, between 7,500 and 15,000 will result in hospitalization.
- ETS exposure increases the prevalence of fluid in the middle ear, a sign of chronic middle ear disease.
- ETS exposure in children irritates the upper respiratory tract and is associated with a small but significant reduction in lung function.
- ETS exposure increases the frequency of episodes and severity of symptoms in asthmatic children. The report estimates that 200,000 to 1,000,000 asthmatic children have their condition worsened by exposure to environmental tobacco smoke.
- ETS exposure is a risk factor for new cases of asthma in children who have not previously displayed symptoms.
Children are particularly vulnerable to the effects of secondhand smoke because they are still developing physically, have higher breathing rates than adults, and have little control over their indoor environments. Children exposed to high doses of secondhand smoke, such as those whose mothers smoke, run the greatest relative risk of experiencing damaging health effects.
- Exposure to secondhand smoke can cause asthma in children who have not previously exhibited symptoms.
- Exposure to secondhand smoke increases the risk for Sudden Infant Death Syndrome.
- Infants and children younger than 6 who are regularly exposed to secondhand smoke are at increased risk of lower respiratory track infections, such as pneumonia and bronchitis.
- Children who regularly breathe secondhand smoke are at increased risk for middle ear infections.
Health Risks to Children with Asthma
- Asthma is the most common chronic childhood disease affecting 1 in 13 school aged children on average.
- Exposure to secondhand smoke can cause new cases of asthma in children who have not previously shown symptoms.
- Exposure to secondhand smoke can trigger asthma attacks and make asthma symptoms more severe.
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1Copyright © the Surgeon General. The information in this article was adapted from the Surgeon General’s reports.
2Copyright © United States Environmental Protection Agency. Articles reprinted with permission.
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