Respiratory symptoms relate to physiological changes and inflammatory markers reflecting central but not peripheral airways. A study in 60-year-old 'healthy' smokers and never-smokers

The aim of this study was to evaluate the relationship between respiratory symptoms, lung function and inflammatory markers in 'healthy' smokers. The study population was recruited from an epidemiological study with subje cts of the same age, 60 years. Only smokers who considered themselves healt hy (n=58) and a random sample of never-smokers (n=34) were investigated. Al l subjects underwent lung function tests-spirometry, carbon monoxide transf er (DLco) and the single-breath N-2 method (N-2 test)-together with high-re solation computed tomography (HRCT). A flexible bronchoscopy with a broncho alveolar lavage (BAL) was performed in 30 smokers and 18 never-smokers. Bro nchial biopsies were also taken. Smokers who reported non-specific respiratory problems, chronic bronchitis and wheezing in a symptom questionnaire had a Tower forced expiratory volum e in 1 sec (FEV1), FEV% and specific airway conductance (sGaw), lung functi on tests supposed to reflect the more central airways, than smokers without respiratory symptoms. A limited number of smokers with occasional non-spec ific respiratory problems also had more cytotoxic T cells (CD8) in bronchia l biopsies. No differences were found in DLco and the Nz test, lung functio n tests supposed to reflect the more peripheral airways including the alveo li, HRCT-diagnosed emphysema or inflammatory markers in blood and BAL betwe en smokers with and without respiratory symptoms. It is concluded that even when smokers consider themselves 'healthy' they h ave mild symptoms that are related more to physiological changes and inflam matory markers that may reflect events in the central ail-ways than to chan ges that may reflect events in the peripheral airways.