While 85 to 90 percent of lung cancer cases are caused by smoking, there is a good (or should we say bad) 10-15% incidence rate where people who have never smoked a day in their lives get lung cancer. This translates in the U.S. alone as 16,000 to 24,000 never-smokers a year dying from the terrible disease.

Suspected causes for lung cancer among never-smokers include genetic susceptibility combined with exposure to certain carcinogens such as asbestos, radon, some solvents, and not the least of which, passive smoking – inhaling others’ cigarette smoke.

To shed some more light on the issue, a group of researches led by Dr. Michael J. Thun, conducted a large-scale composite study using data from 13 other studies from North America, Europe, and Asia spanning 40 years and over 2 million people.

- Men are more likely to die of the disease than women, regardless of age or racial group.

- Men died more from lung cancer than did women in all age and racial groups studied.

- Men and women are almost equally as likely to develop the disease at age 40 and beyond.

- African Americans are more likely to die from the disease than are those of European descent.

- Asians living in Korea and Japan, but not in the U.S., are more likely to die of the disease than those of European descent.

- The disease doesn't seem to be rising among women in the U.S. (Again: The study was among nonsmokers — the rise among women smokers has been well-documented.)

- The disease is more common in East Asian women than in other women.

The study has also showed that the death rate from lung cancer among non-smokers in general has been stable, with no marked increase detected. Also, lung tumors of non-smokers appear to have "different molecular profiles and respond better to targeted therapies" than tumors in smokers' lungs.