Patterns of lung disease in a "normal" smoking population - Are emphysema and airflow obstruction found together?

Study objectives: We determined whether emphysema demonstrated on high-reso lution CT (HRCT)scanning in apparently, well smokers is associated with air flow 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 FEV1 and maximum exp iratory flow at 50% of vital capacity (MEF50) values after suitable correct ions, between subjects with and without parenchymal damage (emphysema and/o r reduced carbon monoxide transfer coefficient [KCO]), and to compare index es of parenchymal damage between subjects with and without airflow obstruct ion. Setting: Radiology and lung function departments of a district general hosp ital. Participants: Eighty current cigarette smokers and 20 lifetime nonsmoking c ontrol subjects (aged 35 to 65 years) who volunteered following publicity i n local media. In all subjects, FEV1 was > 1.5 L; no subjects were known to have lung disease. Measurements and results: FEV1 and MEF50 were measured spirometrically; sta tic lung volumes were measured by helium dilution and body plethysmography; KCO was measured by a single-breath technique. HRCT scans were analyzed fo r emphysema by two radiologists. Of smokers, 25% had HRCT emphysema, genera lly mild; 16.3% and 25% had reduced FEV1 and MEF50, respectively; 12.5% had reduced KCO. Smokers with airflow obstruction were not more likely to have parenchymal damage. Smokers with parenchymal damage did not have reduced a irway function. Nonsmokers generally had normal airways and parenchyma. Conclusions: "Normal" smokers with lung damage had either airflow obstructi on or parenchymal damage, but not generally both.