Never-smokers with COPD at increased risk of lung cancer

[Christine]

Chronic obstructive pulmonary disease (COPD) in individuals who never smoked is associated with lung cancer-related mortality, according to an analysis of data from the American Cancer Society's Cancer Prevention Study II (CPS-II).

A prospective study examining the relationship of emphysema and chronic bronchitis to lung cancer mortality was conducted by Dr. Michelle C. Turner at the University of Ottawa in Ontario, Canada, and associates.

The investigators used 20 years of data on 448,600 participants in CPS-II who had never smoked and were cancer-free at baseline.

As reported in the August issue of the American Journal of Respiratory and Critical Care Medicine, the hazard ratio for lung cancer mortality was 1.66 for emphysema alone and 2.44 for emphysema plus chronic bronchitis. There was no association between chronic bronchitis alone and lung cancer mortality, although the researchers found a trend in that direction for men.

The association between emphysema and lung cancer mortality in never-smokers was stronger in the later years compared with the early years of data.

"This large prospective study strengthens the evidence that increased lung cancer risk is associated with nonmalignant pulmonary conditions, especially emphysema, even in lifelong nonsmokers," the investigators conclude.

The main limitation of the study, Dr. Turner and colleagues point out, "is that we are unable to distinguish whether COPD is in the causal pathway for lung cancer or whether both COPD and lung cancer are related to an underlying exposure, or some combination of both, with or without inherited familial predisposition."

[blaze100]

whether both COPD and lung cancer are related to an underlying exposure,

Yes, probably secondhand smoke. Barb