Cigarette smoking causes cancer

There is clear evidence that breathing in other people’s smoke causes cancer in non-smokers [1, 11, 37, 50]. Second-hand smoke, also known as environmental tobacco smoke or passive smoking, exposes people to cancer-causing chemicals [11].

People who have never smoked have their risk of lung cancer increased by around a quarter if they have colleagues who smoke at work or have a spouse who smokes [50-52]. The risk increases the more second-hand smoke they’re exposed to, workers exposed to the highest levels can have their risk of lung cancer doubled [51, 52].

Second-hand smoke can reach high levels in enclosed spaces such as within the home or inside a car [53-57]. Studies have shown that even when you open the windows levels can be dangerously high [53, 55, 57, 58].

Second-hand smoke also causes other health problems in non-smokers including heart disease and respiratory diseases including asthma in children [37, 50, 59]. And it may increase the risk of pharyngeal and laryngeal cancers [10, 11].

References

10. Cogliano VJ, Baan R, Straif K, et al. Preventable exposures associated with human cancers. Journal of the National Cancer Institute. 2011;103(24):1827–39. View summary on PubMed

11. IARC. A review of human carcinogens. Personal habits and indoor combustions. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. 2012;100(E). View resource

37. US Surgeon General. How Tobacco Smoke Causes Disease : The Biology and Behavioral Basis for Smoking-Attributable Disease.; 2010.

50. Scientific Committee on Tobacco and Health (SCOTH). Secondhand Smoke: Review of evidence since 1998.; 2004.

51. Taylor R, Najafi F, Dobson A. Meta-analysis of studies of passive smoking and lung cancer: effects of study type and continent. International Journal of Epidemiology. 2007;36(5):1048–59. View summary on PubMed

52. Stayner L, Bena J, Sasco AJ, et al. Lung cancer risk and workplace exposure to environmental tobacco smoke. American Journal of Public Health. 2007;97(3):545–51. View resource

53. Blackburn C, Spencer N, Bonas S, Coe C, Dolan A, Moy R. Effect of strategies to reduce exposure of infants to environmental tobacco smoke in the home: cross sectional survey. BMJ (Clinical research ed.). 2003;327(7409):257.