Relationship between reduced forced expiratory volume in one second and the risk of lung cancer: a systematic review and meta-analysis

Abstract

Background: Individuals with severely impaired lung function have an increased risk of lung cancer. Whether milder reductions in forced expiratory volume in 1 second (FEV₁) also increase the risk of lung cancer is controversial. Moreover, there is little consensus on whether men and women have similar risks for lung cancer for similar decreases in FEV₁. Methods: A search was conducted of PubMed and EMBASE from January 1966 to January 2005 and studies that examined the relationship between FEV₁ and lung cancer were identified. The search was limited to studies that were population based, employed a prospective design, were large in size (⩾5000 participants), and adjusted for cigarette smoking status. Results: Twenty eight abstracts were identified, six of which did not report FEV₁ and eight did not adjust for smoking. Included in this report are four studies that reported FEV₁ in quintiles. The risk of lung cancer increased with decreasing FEV₁. Compared with the highest quintile of FEV₁ (>100% of predicted), the lowest quintile of FEV₁ (<∼70% of predicted) was associated with a 2.23 fold (95% confidence interval (CI) 1.73 to 2.86) increase in the risk for lung cancer in men and a 3.97 fold increase in women (95% CI 1.93 to 8.25). Even relatively small decrements in FEV₁ (∼90% of predicted) increased the risk for lung cancer by 30% in men (95% CI 1.05 to 1.62) and 2.64 fold in women (95% CI 1.30 to 5.31). Conclusion: 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.