Black women who never smoked cigarettes may be more likely than white women to die of lung cancer, says a study, published in the Journal of the National Cancer Institute.

According to Michael Thun, M.D., and colleagues who authored the study, an estimated 15,000 lifelong nonsmokers die of lung cancer.

Researchers checked data from two studies conducted in the epidemiology and surveillance research department of the American Cancer Society (ACS).

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 to 84 years old.

Participants’ age, race, education level, spouses’ smoking status, and other factors were also noted in the study.

The 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. 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.

However, smokers account for most lung cancer deaths. Approximately 85 percent to 90 percent of all lung cancer deaths in the United States are caused by active cigarette smoking.

The rate of lung cancer deaths in lifelong nonsmokers has been fairly stable in recent decades.

Among people who never smoked cigarettes, women aren’t more likely than men 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," the researchers note.

However, Thun’s team notes that every year in the U.S., an estimated 15,000 lifelong nonsmokers die of lung cancer.

"Approximately 85 percent to 90 percent of all lung cancer deaths in the United States are caused by active cigarette smoking," they conclude.