Involuntary and Far from Innocuous: The Health Effects of Secondhand Smoke

Posted on March 8th, 2009 by

Involuntary and Far from Innocuous: The Health Effects of Secondhand Smoke

By Kari Bohlke, ScD

“Today, massive and conclusive scientific evidence documents adverse effects of involuntary smoking on children and adults, including cancer and cardiovascular diseases in adults, and adverse respiratory effects in both children and adults.”

- 2006 Surgeon General’s report1

There is no safe level of exposure to secondhand smoke, and the evidence of adverse effects on health is incontrovertible. These are important messages from a 2006 report from the U.S. Surgeon General. Fortunately, steps to reduce the exposure of nonsmokers to tobacco smoke are beginning to make a difference. These benefits will likely expand across the lifespan, through reductions in sudden infant death syndrome (SIDS), ear infections, and respiratory problems in infants and children and reductions in cancer and heart disease in adults.

What Is Secondhand Smoke?

Secondhand smoke, also known as environmental tobacco smoke or involuntary smoking, consists of both sidestream smoke (smoke from the burning end of the cigarette) as well as mainstream smoke (smoke exhaled by smokers). Sidestream smoke makes up at least half the smoke generated and tends to contain smaller particles and a higher concentration of carcinogens (cancer-causing agents) than mainstream smoke.2

Secondhand smoke is classified as a known human carcinogen by the National Toxicology Program as well as the International Agency for Research on Cancer. It contains at least 250 chemicals that are known to be toxic or carcinogenic.2 Carcinogens present in secondhand smoke include polycyclic aromatic hydrocarbons, N-nitrosamines, formaldehyde, acetaldehyde, benzene, butadiene, and metals such as cadmium and lead.3

And risk of cancer is just the beginning of the story. Secondhand smoke also has clear adverse effects on the respiratory and cardiovascular systems. In fact, the estimated number of cardiovascular deaths due to secondhand smoke far exceeds the estimated number of lung cancer deaths due to secondhand smoke.4

An Evolving Field

The 1972 Surgeon General’s report on the health effects of smoking noted, “an atmosphere contaminated with tobacco smoke can contribute to the discomfort of many individuals.”5 While this is certainly true, it’s now apparent that the adverse effects of secondhand smoke go well beyond discomfort.

Evidence for a link between secondhand smoke and lung cancer and other health problems began to accumulate over the next decade. A study conducted in Japan and published in 1981, for example, reported that nonsmoking women married to smokers were significantly more likely to develop lung cancer than nonsmoking women married to nonsmokers.6

The first Surgeon General’s report devoted entirely to the topic of secondhand smoke was published in 1986.7 This report concluded that secondhand smoke is a cause of disease, including lung cancer, in healthy nonsmokers and that secondhand smoke causes respiratory problems in children. The report also noted that separating smokers and nonsmokers within the same air space (such as in a restaurant or airplane) reduces but does not eliminate exposure to secondhand smoke.

In 2006, in response to an increasing amount of scientific evidence regarding the adverse health effects of secondhand smoke, the Surgeon General released a second report on secondhand smoke.8 The 2006 report links secondhand smoke with a broader range of health problems than did the previous reports.

Health Effects on Adults and Children

Exposure to secondhand smoke has been clearly linked with an increased risk of lung cancer in nonsmokers. Secondhand smoke is thought to account for roughly 3,000 lung cancer deaths each year.4 Combined analyses of previously published studies suggest that living with a smoker increases a nonsmoker’s risk of lung cancer by 20 to 30 percent. Evidence for a link between secondhand smoke and other types of cancer is suggestive but not conclusive.9

Secondhand smoke also causes coronary heart disease, resulting in an estimated 46,000 deaths each year among U.S. nonsmokers.4 The harmful effects of secondhand smoke on the heart, the blood, and the blood vessels increase the risk of heart attack and may also make a heart attack more severe than it would have been otherwise. Even brief exposure to secondhand smoke can damage the lining of blood vessels and make blood platelets stickier.10

The picture is also grim for children. Exposure to secondhand smoke has been linked with SIDS; lower respiratory illness such as bronchitis and pneumonia; ear infections; cough, phlegm, wheeze, and breathlessness; and reduced lung function.11

The Success of Smoke-free Policies

Policies to eliminate smoking in indoor public places have had a dramatic effect on exposure to secondhand smoke in the United States. Between 1988 and 2002, the percentage of U.S. nonsmokers who had evidence of cotinine in their blood fell from 88 to 43 percent.12 Cotinine is a byproduct of nicotine metabolism and indicates recent exposure to tobacco smoke. Also during this time period, the amount of cotinine in the blood of nonsmokers fell by roughly 70 percent. Because smoking rates did not change greatly during this time period, these improvements are likely due to a reduction of smoking in public places.12

The experience of New York state illustrates the impact of smoking bans on exposure to secondhand smoke. In July 2003 New York issued a statewide ban on smoking in indoor workplaces and public places. Between June 2003 and June 2004, average cotinine levels in nonsmokers dropped by 47 percent. In addition, the percentage of respondents who reported recent exposure to secondhand smoke in a restaurant fell from 19.8 to 3.1 percent. Exposure to secondhand smoke in a bar fell from 52.4 to 13.4 percent.13

One area in which improvement is still needed is the exposure of children to secondhand smoke in the home. Children in the United States are more likely than nonsmoking adults to be exposed to secondhand smoke and to have higher blood cotinine levels.12 Protecting children from secondhand smoke will require that parents and other family members avoid smoking inside the home or, better still, stop smoking entirely. Increasing ventilation within the home or smoking in a different room from the child does not eliminate the child’s exposure to tobacco smoke.1 This is an important point because there is no safe level of exposure to secondhand smoke.

Continued Progress Is Imperative

For those of us who grew up with cigarette smoke in airplanes and restaurants (as well as at home), bans on smoking in public places offer much-needed relief. There is clearly room for improvement, however, and a continued focus on both smoking cessation and the expansion of smoke-free environments remains important. Ongoing progress is particularly critical for children, who have little control over their environment and much to lose. As C. Everett Koop, MD, said in the preface to the 1986 Surgeon General’s report on involuntary smoking, “The right of smokers to smoke ends where their behavior affects the health and well-being of others…”7

Useful Links

Health Effects of Secondhand Smoke

The following are some recent statistics on the estimated number of deaths and illnesses that occur annually in the United States as a result of exposure to secondhand smoke.4

Lung cancer deaths

3,400

Cardiac deaths

46,000

SIDS deaths

430

Low birth weight

24,500

Lower respiratory illnesses* (children)

150,000 to 300,000

Asthma episodes (children)

202,300

Visits for ear infections (children)

790,000

*Includes pneumonia and bronchitis

Some of the Harmful Components of Secondhand Smoke14

Cancer-causing chemicals:

  • Formaldehyde
  • Benzene
  • Polonium-210 (210Po)
  • Vinyl chloride

Toxic metals:

  • Chromium
  • Arsenic
  • Lead
  • Cadmium

Poison gases:

  • Carbon monoxide
  • Hydrogen cyanide
  • Butane
  • Ammonia
  • Toluene

Another Important Cause of Lung Cancer in Nonsmokers: Radon

Radon is a radioactive gas produced by the decay of naturally occurring uranium in soil and water. It has no color, odor, or taste.15 In the United States, radon is the second-leading cause of lung cancer (smoking is the first).16 Worldwide, the World Health Organization estimates that up to 15 percent of lung cancers are caused by radon.17

For most individuals, homes are the greatest source of radon exposure. An estimated one in 15 U.S. homes has high levels of radon.18 Do-it-yourself radon test kits are available at many hardware stores, and testing can also be performed by a professional. If the test identifies high radon levels, it may be possible to reduce levels by installing a radon venting system or other measures. During the construction of new homes, radon-reduction measures can be built into the house from the start.

For radon information from the Environmental Protection Agency, visit http://www.epa.gov/radon.

References:


1 US Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General-Executive Summary. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006. Available at: http://www.surgeongeneral.gov/library/secondhandsmoke. Accessed March 12, 2008.

2 US Department of Health and Human Services. Report on Carcinogens, 11th ed. US Department of Health and Human Services, Public Health Service, National Toxicology Program. Available at: http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/s176toba.pdf. Accessed March 12, 2008.

3 US Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Chapter 2: Toxicology of Secondhand Smoke. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006. Available at: http://www.surgeongeneral.gov/library/secondhandsmoke. Accessed March 12, 2008.

4 California Environmental Protection Agency. Proposed Identification of Environmental Tobacco Smoke as a Toxic Air Contaminant. Part B: Health Effects. Sacramento: California Environmental Protection Agency, Office of Environmental Health Hazard Assessment, 2005. Available at: http://www.oehha.ca.gov/air/environmental_tobacco/pdf/app3partb2005.pdf. Accessed March 12, 2008.

5 US Department of Health, Education, and Welfare. The Health Consequences of Smoking. A Report of the Surgeon General: 1972. Washington DC: US Department of Health, Education, and Welfare; Public Health Service; Health Services and Mental Health Administration; 1972. DHEW Publication No. (HSM) 72-7516. Available at: http://www.cdc.gov/tobacco/data_statistics/sgr/previous_sgr.htm. Accessed March 12, 2008.

6 Hirayama T. Non-smoking wives of heavy smokers have a higher risk of lung cancer: A study from Japan. British Medical Journal (Clinical Research Edition). 1981;282:183-85.

7 US Department of Health and Human Services. The Health Consequences of Involuntary Smoking. A Report of the Surgeon General. Rockville, Maryland: US Department of Health and Human Services, Public Health Service, Centers for Disease Control, Center for Health Promotion and Education, Office on Smoking and Health, 1986. DHHS Publication No. (CDC) 87-8398. Available at: http://www.cdc.gov/tobacco/data_statistics/sgr/previous_sgr.htm. Accessed March 12, 2008.

8 US Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006. Available at: http://www.surgeongeneral.gov/library/reports.htm. Accessed March 12, 2008.

9 US Department of Health and Human Services. The Health Consequences of Involuntary Exposure to Tobacco Smoke: A Report of the Surgeon General. Chapter 7:Cancer Among Adults from Exposure to Secondhand Smoke. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006. Available at: http://www.surgeongeneral.gov/library/secondhandsmoke. Accessed March 12, 2008.

10 Centers for Disease Control and Prevention. Smoking & Tobacco Use Fact Sheet: Secondhand Smoke Causes Heart Disease. Available at: http://www.cdc.gov/tobacco/data_statistics/Factsheets/HeartDisease.htm. Accessed March 12, 2008.

11 US Department of Health and Human Services. The Health Consequences of InvoluntaryExposure to Tobacco Smoke: A Report of the Surgeon General. Chapter 6:Respiratory Effects in Children from Exposure to Secondhand Smoke. Atlanta: US Department of Health and Human Services, Centers for Disease Control and Prevention, Coordinating Center for Health Promotion, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006. Available at: http://www.surgeongeneral.gov/library/secondhandsmoke. Accessed March 12, 2008.

12 Pirkle JL, Bernert JT, Caudill SP, Sosnoff CS, Pechacek TF. Trends in the exposure of nonsmokers in the U.S. population to secondhand smoke: 1988-2002. Environmental Health Perspectives. 2006;114(6):853-58.

13 Centers for Disease Control and Prevention. Reduced secondhand smoke exposure after implementation of a comprehensive statewide smoking ban-New York, June 26, 2003–June 30, 2004. Morbidity and Mortality Weekly Report. 2007;56(28):705-8.

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