The relationship between symptoms and functional abnormalities in clinically healthy cigarette smokers.

Because a number of "early tests" may now be used to measure abnormalities of lung function in cigarette smokers with normal airflow rates, we evaluated the symptoms of cough, sputum, wheezing, and shortness of breath in 60 nonsmokers and 49 smokers to determine whether these symptoms correlated with measurements of lung function that are believed to be altered by mild obstruction. One or more symptoms were present in 5 per cent of the nonsmokers and 90 per cent of the smokers. Individual symptoms, sums of symptoms (symptoms score), and various combinations of symptoms correlated poorly or not at all to measured values for dynamic lung compliance, closing volume, closing capacity, slope of Phase III, and helium flow-volume curves. The symptoms score correlated negatively (P less than 0.05) with forced maximal expiratory flow at 50 per cent of vital capacity. Inasmuch as the serious consequences of chronic airway obstruction are related to abnormalities of lung function, it is likely the function tests will prove more useful than symptoms to reveal smokers at risk to develop chronic obstructive pulmonary disease. Symptoms cannot be used to detect smokers who are liable to have functional abnormalities suggestive of mild peripheral airway obstruction.