Table 1.

Epidemiological studies linking COPD and lung cancer

Study	Year	Key Finding	Reference
Skillrud and colleagues	1986	First report of increased lung cancer incidence for airflow limitation (FEV1, <70%)	8
Tockman and colleagues	1987	First report of increased lung cancer mortality for airflow limitation (FEV1, <60%)	9
Wasswa-Kintu and colleagues	2005	Meta-analysis of 204,990 subjects demonstrating increased lung cancer incidence with airflow obstruction	10
de Torres and colleagues	2007	First report showing that radiographic emphysema increases lung cancer incidence	11
Wilson and colleagues	2008	Entirety of lung cancer risk attributable to radiographic emphysema	12
Zulueta and colleagues	2012	Increased lung cancer mortality for presence of radiographic emphysema	13
Young and colleagues	2015	Presence of COPD doubles risk of lung cancer diagnosis during screening	5

Definition of abbreviations: COPD = chronic obstructive pulmonary disease; FEV₁ = forced expiratory volume in 1 second.