Jul 14, 2005 – Canadian scientists have found a significant link between small decreases in lung function and an elevated risk of lung cancer, with a stronger association in women than men.

Individuals with severely impaired lung function have an increased risk of lung cancer. Whether milder reductions in FEV1 also increase the risk of lung cancer is controversial, say S Wasswa-Kintu (University of British Columbia, Vancouver) and colleagues.

They add: Moreover, there is little consensus on whether men and women have similar risks for lung cancer for similar decreases in FEV1.

To investigate this issue, the researchers reviewed all prospective, population-based studies conducted between 1966 and 2005 that involved at least 5000 participants and examined the relationship between FEV1 and lung cancer, adjusting for smoking status.

Reporting in the journal Thorax, the team identified 28 abstracts, although six of these did not report FEV1, and eight failed to adjust for smoking.

Analysis of four of these studies that reported FEV1 in quintiles revealed that the risk of lung cancer increased as FEV1 decreased. Specifically, there were 2.23 and 3.97-fold increased risks for men and women, respectively, with FEV1 in the lowest quintile (less than 70% of predicted) compared with the highest quintile (100% of predicted).

Notably, the authors report that even relatively small decrements in FEV1 increased the risk of lung cancer, with a 10% FEV1 drop increasing a person s lung cancer risk by 30% in men and 2.64-fold in women.

Wasswa-Kintu et al summarize that reduced FEV1 is strongly associated with lung cancer.

Even a relatively modest reduction in FEV1 is a significant predictor of lung cancer, especially among women, they add.

Thorax 2005; 60: 570 575