According to the results of a combined analysis of previously published studies, nonsmoking women married to men who smoke are more likely to develop lung cancer than nonsmoking women married to nonsmoking men. These results were published in the International Journal of Epidemiology.
Exposure to second-hand smoke (also known as environmental tobacco smoke, or ETS) is the third-leading cause of lung cancer in the United States. It is thought to account for roughly 3,000 lung cancer deaths each year, 1,000 of which occur in nonsmokers.
Environmental tobacco smoke is classified as a known human carcinogen by both the U.S. National Toxicology Program as well as the International Agency for Research on Cancer (part of the World Health Organization).
To summarize the available evidence regarding the link between risk of lung cancer and marriage to a smoker, researchers combined information from 55 previously published studies. The analysis focused on risk of lung cancer among nonsmoking women married to men who smoke.
- Compared to nonsmoking women married to nonsmoking men, risk of lung cancer was 27% higher among nonsmoking women married to men who smoke.
- An increased risk of lung cancer among nonsmoking women married to men who smoke was observed in studies conducted in North America, Asia, and Europe.
These results provide additional evidence that exposure to environmental tobacco smoke increases the risk of lung cancer. The researchers conclude: "The abundance of evidence, consistency of finding across continent and study type, dose-response relationship and biological plausibility, overwhelmingly support the existence of a causal relationship between passive smoking and lung cancer."
 US Environmental Protection Agency. Indoor Air – Radon. Health Risks. Exposure to Radon Causes Lung Cancer in Non-Smokers and Smokers Alike. http://www.epa.gov/radon/healthrisks.html. (Accessed January 8, 2008).
 Report on Carcinogens, Eleventh Edition; U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program.
 International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Volume 83. Tobacco Smoke and Involuntary Smoking. Summary of Data Reported and Evaluation. Available at: http://monographs.iarc.fr/ENG/Monographs/vol83/volume83.pdf (Accessed January 8, 2008)
 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;36:1048-1059.