SUNDAY, Oct. 25 (HealthDay News) -- Women may be more vulnerable than men to the carcinogens and other noxious substances in cigarette smoke, a growing body of research suggests.

In one study of nearly 700 people with lung cancer, Swiss experts found that women tended to be younger when they received the diagnosis, even though they smoked less than the men who developed lung cancer.

In another study, researchers from Harvard University and the University of Bergen in Norway evaluated more than 950 men and women with chronic obstructive pulmonary disease (COPD), known to be linked to smoking. The result: The women with COPD were younger when they got the diagnosis and had smoked less than the men with the respiratory ailment.

"Maybe women are more susceptible to the lung-damaging effects of smoking," said Dr. Inga-Cecilie Soerheim, a visiting research fellow at Harvard and a researcher at the University of Bergen, who led the COPD study. She presented the findings in May at the American Thoracic Society's annual conference.

In fact, several other studies in the past 20 years have suggested that female smokers may be more susceptible to lung cancer than male smokers.

And Soerheim and her colleague, Dr. Dawn L. DeMeo, an assistant professor of medicine at Harvard Medical School and Brigham and Women's Hospital in Boston, found that, in 2000, the number of women dying from COPD surpassed the number of men, although the researchers aren't sure why.

However, Dr. Michael Thun, the emeritus director of epidemiology research at the American Cancer Society, isn't as quick to embrace the theory that women are more susceptible to lung cancer.

"The actual evidence suggests that men and women are remarkably similar in their risk of developing lung cancer -- with or without smoking," he said.

But, Thun added, "the types of lung cancer they get are different," referring to the sites in the lung where the cancer is likely to occur in women and men.

Addressing the new COPD research, which seems to say that women are more vulnerable, Thun said other factors might be at play. They include women's longer life expectancy, thus making them more likely to develop the condition.

Thun said the focus on possible gender differences is missing the point. Instead, he said, health experts -- and the public -- need to focus on what is certain: that smoking is an enormous contributor to both lung cancer and COPD.

"If they [smokers] quit before age 50, they avoid most of the risk," he said, citing published research.

And once they do quit, Thun said, women and men can move on to other known ways to reduce their risk for lung cancer, such as avoiding exposure to secondhand smoke.

Lung cancer is the leading cause of cancer death for both men and women in the United States. More people die of lung cancer than of colon, breast and prostate cancers combined, according to the American Cancer Society.

The society estimates that there will be more than 219,000 new cases of lung cancer diagnosed this year and that 159,390 people will die from the disease.

More information

The American Cancer Society has more on smoking and lung cancer.

SOURCES: Michael Thun, M.D., emeritus director of epidemiological research, American Cancer Society, Atlanta; Dawn L. DeMeo, M.D., M.P.H., researcher, Channing Laboratory, and assistant professor, Harvard Medical School and Brigham and Women's Hospital, Boston; American Cancer Society Cancer Facts & Figures 2009; American Thoracic Society International Conference, May 15-20, 2009, San Diego; European Society for Medical Oncology, news release, May 3, 2009

Copyright © 2009 ScoutNews, LLC. All rights reserved.