Patterns of Lung Disease in a “Normal” Smoking Population

• Published in: Chest Vol. 120; no. 3; p. 743
• Main Authors: Kimberley D. Clark, Nigel Wardrobe-Wong, John J. Elliott, Peter T. Gill, Nicholas P. Tait, Phillip D. Snashall
• Format: Journal Article
• Language: English
• Published: American College of Chest Physicians 01.09.2001
• ISSN: 0012-3692; 1931-3543
• DOI: 10.1378/chest.120.3.743

Study objectives: We determined whether emphysema demonstrated on high-resolution CT (HRCT) scanning in apparently well smokers is associated with airflow obstruction. Interventions: Lung function testing and limited HRCT scanning. Design: Lung function measurements and scans were analyzed independently of each other. We used analysis of covariance to compare FEV 1 and maximum expiratory flow at 50% of vital capacity (MEF 50 ) values after suitable corrections, between subjects with and without parenchymal damage (emphysema and/or reduced carbon monoxide transfer coefficient[ K co ]), and to compare indexes of parenchymal damage between subjects with and without airflow obstruction. Setting: Radiology and lung function departments of a district general hospital. Participants: Eighty current cigarette smokers and 20 lifetime nonsmoking control subjects (aged 35 to 65 years) who volunteered following publicity in local media. In all subjects, FEV 1 was > 1.5 L; no subjects were known to have lung disease. Measurements and results: FEV 1 and MEF 50 were measured spirometrically; static lung volumes were measured by helium dilution and body plethysmography; K co was measured by a single-breath technique. HRCT scans were analyzed for emphysema by two radiologists. Of smokers, 25% had HRCT emphysema, generally mild; 16.3% and 25% had reduced FEV 1 and MEF 50 , respectively; 12.5% had reduced K co . Smokers with airflow obstruction were not more likely to have parenchymal damage. Smokers with parenchymal damage did not have reduced airway function. Nonsmokers generally had normal airways and parenchyma. Conclusions: “Normal” smokers with lung damage had either airflow obstruction or parenchymal damage, but not generally both.