SMALL AIRWAYS DISEASE

Over the last 10 years the non‐specific term “small airways disease” has been applied to a number of histologic lesions seen in the peripheral airways of smokers. It is becoming recognized that airway inflammation is the most important of these lesions. This pathology may be the precursor to the subsequent development of emphysema and is an important cause of the functional abnormality in smokers. A current hypothesis is that small airways disease may be detected early in the smoking careers of subjects who later develop chronic respiratory disability. In these individuals particularly, complete cessation of smoking should be the primary therapeutic goal. With the recent development of special tests to assess small airways function, the presence of small airways disease can be detected in asymptomatic smokers who may have normal routine lung function tests. However, most of the tests to assess airway function are also influenced by other physiological factors such as loss of elastic recoil. We await the results of long term epidemiological studies to confirm the above hypothesis that early small airways disease leads to chronic disability. Without such confirmatory evidence, the routine use of these special tests cannot at present be advocated.