Nonsmoking Women Married to Smokers Face No Increase in Breast Cancer Mortality
A large new study reports that nonsmoking women married to smoking men do not have an increased risk of dying of breast cancer, a finding that contradicts the results of earlier studies.
Daniel Wartenberg, Ph.D., Environmental and Occupational Health Sciences Institute, Piscataway, N.J., and colleagues analyzed data from a major prospective study conducted by the American Cancer Society. They found that the breast cancer death rate for nonsmoking women whose husbands smoked was nearly identical to that for nonsmoking women whose husbands did not smoke. These results disagree with previous studies that reported an increase in breast cancer risk among women exposed to environmental tobacco smoke (ETS). However, the authors note that the prospective design, the large number of women involved, and the reporting of ETS exposure by both spouses give credence to the current study. These results appear in the October 18 issue of the Journal of the National Cancer Institute.
The study involved never-smoking married women who were selected from a prospective mortality study of about 1.2 million U.S. men and women begun by the American Cancer Society in 1982. This group of 146,488 women is a convenience sample from all 50 states, the District of Columbia, and Puerto Rico. The median age of the female study participants in 1982 was 56 years, and 75% of the women were between the ages of 45 and 70 years.
All participants completed a mailed confidential questionnaire, and exposure to ETS was defined in two ways. The primary analyses defined exposure to ETS as active smoking by the spouse as reported in his questionnaire and considered both amount and duration of spousal smoking. A second definition of ETS exposure was derived directly from each womanâ€™s report of the number of hours per day that she was "exposed to the smoke of others" at home, at work, and elsewhere.
The vital status of study participants was determined from the month of enrollment through December 31, 1994, using two approaches. Volunteers made personal inquiries in September 1984, 1986, and 1988 to determine whether enrollees were alive or deceased, and status through the end of 1994 was determined through automated linkage using the National Death Index.
After 12 years of follow-up, 669 deaths due to breast cancer were observed among the 146,488 never-smoking married women who were cancer free at study entry. However, breast cancer mortality rates did not differ significantly among never-smoking women married to nonsmokers, former smokers, or current smokers. Also, the breast cancer mortality rates did not show a statistically significant increase with the number of packs of cigarettes smoked by the spouse, the duration of spousal smoking, or the pack-years of smoking. The authors did find data suggesting that women married before age 20 years to smokers may be at increased risk of dying of breast cancer, and they note that this observation warrants follow-up.
Contact: Susan Preston, Environmental and Occupational Health Sciences Institute, (973) 972-7265; fax: (973) 972-7272.
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