A new study sheds light on lung cancer deaths in lifelong nonsmokers.
The study, published in the Journal of the National Cancer Institute, includes these findings:
Among people who never smoked cigarettes, women aren’t more likely than men to die of lung cancer. The rate of lung cancer deaths in lifelong nonsmokers has been fairly stable in recent decades. Black women who never smoked cigarettes may be more likely than white women to die of lung cancer.
“Contrary to clinical perception, the lung cancer death rate is not higher in female than in male never smokers and shows little evidence of having increased over time in the absence of smoking,” write Michael Thun, MD, and colleagues in theJournal of the National Cancer Institute.
Thun works in the epidemiology and surveillance research department of the American Cancer Society (ACS).
Lung Cancer Deaths in Lifelong Nonsmokers
Smokers account for most lung cancer deaths.
“Approximately 85 percent- 90 percent of all lung cancer deaths in the United States are caused by active cigarette smoking,” write Thun and colleagues.
However, Thun’s team notes that every year in the U.S., an estimated 15,000 lifelong nonsmokers die of lung cancer.
Thun and colleagues checked data from two ACS studies. One study ran from 1959 to 1972. The other spanned the years from 1982 to 2000. Each included more than 940,000 people who reported being lifelong nonsmokers, lived in the U.S., and were 35-84 years old.
Participants’ age, race, education level, spouses’ smoking status, and other factors were also noted in the study.
Results by Sex, Race
Thun’s team estimates that in the later ACS study, a rate of 17 out of 100,000 lifelong nonsmoking men per year died of lung cancer, compared with nearly 15 per 100,000 women who were lifelong nonsmokers.
The gender gap was a bit wider in the earlier ACS study. What changed? Lung cancer death rates rose for nonsmoking women aged 70-84, possibly because of improvements in lung cancer diagnosis, the researchers write.
The later ACS study also showed that compared with white nonsmoking women, black nonsmoking women were more likely to die of lung cancer. A similar but weaker pattern was seen among black and white nonsmoking men, but that finding may have been due to chance.
Future studies should check whether lung cancer is more common, more deadly, or more often misdiagnosed in nonsmoking blacks than whites, write Thun and colleagues.
By Miranda Hitti, reviewed by Louise Chang, MD
SOURCES: Thun, M. Journal of the National Cancer Institute, May 17, 2006; vol 98: pp 691-699. News release, American Cancer Society.