Health effects of secondhand smoke

There is a large amount of evidence that breathing in other people's tobacco smoke is bad for your health.

Findings from major scientific reviews in Australia, Europe and the United States conclude that exposure to secondhand smoke causes:

In adults

• Heart disease
• Lung cancer
• Irritation of the eyes and nose

In children and infants

• Sudden infant death syndrome (SIDS or cot death)
• Lower birthweight (where the pregnant mother was exposed to SHS)
• Bronchitis, pneumonia and other lung/airways infections
• Wheeze illnesses in early childhood
• Middle ear disease (otitis media or ‘glue ear', middle ear effusion)
• Respiratory symptoms including cough, phlegm, wheeze and breathlessness
• Higher rates and worsening of asthma
• Lower level of lung function during childhood (i.e. they cannot breathe in as deeply or breathe out as hard as they would otherwise)

Exposure to secondhand smoke is also linked to a number of other diseases and conditions including other cancers, stroke, chronic obstructive pulmonary disease (COPD), development of childhood asthma, adult asthma and other breathing problems, meningococcal disease in children, and preterm delivery of babies.

Heart disease

Exposure to secondhand smoke increases the risk of coronary heart disease in non-smokers.  The majority of deaths from secondhand smoke are from heart disease.

The risk of heart disease for non-smokers with long term exposure to tobacco smoke is between 25% and 30% greater than that for non-exposed non-smokers. This increased risk of heart disease from secondhand smoke is about one-third the increased risk of active smoking. 

Inhaling secondhand smoke causes both short and long term harm to the heart.  It reduces the amount of oxygen carried in the bloodstream, making damage to the heart and tissues more likely. Chemicals in tobacco smoke also help clog the arteries, and cause blood clots.  Over many years, these effects may lead to heart attack.

Research also suggests that non-smokers who have been exposed to tobacco smoke may have an increased risk of stroke and atherosclerosis (disease of the blood vessels).

Cancer

Exposure to secondhand smoke causes lung cancer in non-smokers.

Non-smokers who suffer long term exposure to environmental tobacco smoke have between 20% and 30% higher risk of developing lung cancer than non-exposed non-smokers.

Research suggests that secondhand smoke may be a cause of breast cancer in younger women (before menopause) and of nasal sinus cancer. More research is needed before these findings can be confirmed.

Some evidence suggests when a pregnant mother and a child is exposed to secondhand smoke before and after birth, her child may have an increased risk for certain childhood cancers, such as leukemias, lymphomas and brain cancer.  More research is needed before this can be confirmed.

 

References

 1. U.S. Department of Health and Human Services. The health consequences of involuntary exposure to tobacco smoke: a report of the Surgeon General. Atlanta, Ga.: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion, Office on Smoking and Health; 2006.

2. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Tobacco smoke and involuntary smoking IARC monographs on the evaluation of carcinogenic risks to humans. Lyon, France: International Agency for Research on Cancer; 2004.

3. National Health and Medical Research Council. The health effects of passive smoking. November 1997. A scientific information paper. Canberra: Australian Government Publishing Service, 1997.

4. U.S. 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.

5. United States Environmental Protection Agency. Respiratory health effects of passive smoking: Lung cancer and other disorders. Washington DC: United States Environmental Protection Agency, December 1992. (Publication EPA/600/6-90/006F,)

6. Arcavi L, Benowitz NL. Cigarette smoking and infection. Arch Intern Med. 2004;164(20):2206-2216.

7. Robinson P, Taylor K, Nolan T. Risk-factors for meningococcal disease in Victoria, Australia, in 1997. Epidemiol Infect. 2001;127(2):261-268.

8. McCall BJ, Neill AS, Young MM. Risk factors for invasive meningococcal disease in southern Queensland, 2000-2001. Intern Med J. 2004;34(8):464-468.

9. Kriz P, Bobak M, Kriz B. Parental smoking, socioeconomic factors, and risk of invasive meningococcal disease in children: a population based case-control study. Arch Dis Child. 2000;83(2):117-121.

10. Barnoya J, Glantz SA. Cardiovascular effects of secondhand smoke: nearly as large as smoking. Circulation. 2005;111(20):2684-2698.

11.Glantz SA, Parmley WW. Even a little secondhand smoke is dangerous. JAMA. 2001;286(4):462-463.