In heavy smokers, limited airflow is correlated with increased risk of lung cancer, according to researched published in the Annals of the American Thoracic Society.

Raewyn J. Hopkins, M.P.H., from the University of Auckland in New Zealand, and colleagues examined the correlation between the severity of airflow limitation and lung cancer risk in a prospective study of older heavy smokers from the American College of Radiology Imaging Network sub-cohort of the National Lung Screening Trial (NLST-ACRIN). Airflow limitation was classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade 1 to 4.

The researchers found that 35 and 65 percent of the NLST-ACRIN cohort of 18,473 screening participants had airflow limitation and no airflow limitation, respectively. Seven hundred fifty-eight lung cancer cases were prospectively identified. Lung cancer incidence was 3.78/1,000 person-years for those with no airflow limitation. For those with airflow limitation, incidence rates increased in a simple linear relationship: 6.27, 7.86, 10.71, and 13.25/1,000 person-years for GOLD 1, GOLD 2, GOLD 3, and GOLD 4, respectively. Compared with the reference group, all relationships were significant (P ? 0.0001).