Abstract
Objective: We clarified the characteristics of lung ages calculated on the basis of 1-second forced expiratory volume and examined problems with using them.
Methods: We divided 9,123 people who underwent respiratory function testing in ningen dock in fiscal 2008 into a smokers group, a past smokers group and a non-smokers group. They were compared for respiratory function, lung age and lung age difference (lung age - actual age) and inflammation findings and we examined optimal lung age difference cut-off points for suspected COPD. For heavy smokers, differences between a lung age (+) group and a lung age (-) group were also examined.
Results: COPD was suspected in 7.5% of smokers and past smokers and 2.0% of non-smokers. At 0.099±0.206 mg/dL and 0.094±0.199 mg/dL, respectively, the high-sensitivity CRP level in the smokers and past smokers groups was significantly higher than that in the non-smokers, of 0.075±0.167 mg/dL (p<0.001) but the difference between smokers and past smokers was not significant. The optimal lung age difference cut-off point for suspected COPD was 16.6 years. Around 17.5% of the heavy smokers came under the lung age (-) group and in these subjects, pulmonary capacity was higher and evidence of inflammation slight.
Conclusions: As lung age is connected with smoking history it can play an important role in smoking cessation counseling. However, it is necessary to keep in mind that in spite of smoking a large number of cigarettes, there are individuals with a lung age younger than their actual age who have a high pulmonary capacity and show only a slight inflammatory reaction. In addition, our findings suggest that inflammation due to smoking persists in past smokers.
