Abstract
Background: The rate of forced expiratory volume in 1 second (FEV1) decline is a marker of chronic obstructive pulmonary disease risk. To date, limited longitudinal data exist on airflow obstruction (COPD) and FEV1 decline in Japan.
Aims and objectives: The aim of this study was to investigate the rate of FEV1 decline by smoking habits over a 12-year periods in Japanese males.
Methods: The study included 913 male subjects, aged 30-76 years at baseline, who underwent lung function tests at a medical check-up in 1994 (baseline), 1999, and 2006. The study group consisted of 263 persistent never smokers, 296 early quitters (those who stopped smoking between 1994 and 2006), 117 late quitters 8those who stopped smoking between 1999 and 2006), and 237 persistent smokers without airflow obstruction at baseline. Airflow obstruction (AO) was defined as FEV1/FVC<0.7 and 5th percentile lower limit of normal (FEV1/FVC<LLN).
Results: Mean annual decline in FEV1 over a 12-year periods were -35.0 ml/yr in persistent never smokers, -37.9 ml/yr in early quitters, -40.7 ml/yr in late quitters, and -44.8 ml/yr in persistent smokers. Mean annual decline in FEV1 over a 12-year periods defined using the fixed criteria and the LLN criteria were -34.6 ml/yr, -34.3ml/yr in persistent never smokers without AO, -42.3 ml/yr, -42.3 ml/yr in persistent smokers without AO, -60.3 ml/yr, and -56.7 ml/yr in persistent smokers with AO, respectively.
Conclusions: Persistent smokers with AO had a significant reduced FEV1 decline compared with those in persistent never smokers and current smokers without AO. Our study confirmed that early cessation of smoking may reduce the FEV1 decline and prevent the development of AO among smokers.
- © 2011 ERS