2016 Volume 3 Issue 1 Pages 3-6
Background and Methods: To evaluate differences in the frequency of airflow obstruction between the presence and absence of emphysematous changes (CT emphysema) detected in low-dose CT screening, we performed a retrospective cohort study in males who annually underwent a health check-up (Ningen Dock) for employees over a long period. Among males with a smoking history (≥ 20 pack-years) who underwent low-dose CT screening in a health check-up between April 1998 and March 2006, those who also underwent check-ups between April 2009 and March 2012 were included as the subjects. The subjects consisted of 2,164 males (285 in the CT emphysema group and 1,879 in the non-emphysema group). Their mean age was 51.4 years, and the mean amount of smoking was 33.4 pack-years. Pulmonary function tests were performed 11.5 times during a mean period of 12.1 years.
Results: The cumulative frequency of moderate or severe airflow obstruction, which was defined as both forced expiratory volume % in one second (FEV1%) < 70% and percent forced expiratory volume in one second (%FEV1) < 80%, in the CT emphysema group was 37.2%, markedly higher than that (14.8%) in the non-emphysema group. Multivariate analysis revealed that the odds ratio of moderate or severe airflow obstruction due to CT emphysema was 3.21 (2.24–4.58), and that due to smoking continuation was 8.16 (3.54–18.81).
Conclusion: CT emphysema may be a radiological sign of future airflow obstruction risk.
