The subjects with asthma were nonsmokers or had less than a 20 pack-year smoking history and onset of symptoms before age 30 years. The subjects with COPD were all heavy smokers (mean smoking history, 82.8 ±16.2 pack-years) and had onset of symptoms after age 40 years. Two additional nonsmoking subjects, who were referred for aerosol treatment because of wheezing, had bronchitis. One 59-year-old subject with bronchitis had a history of productive cough for “several” months for two consecutive years. The other subject with bronchitis was a 39-year-old woman who had a productive cough for four weeks. Neither subject had fever.

The data on the COPD and subjects with bronchitis were analyzed both with bronchitis and COPD subjects combined, and with the COPD subjects analyzed separately. Fourteen of the 16 subjects were taking bronchodilator medication at the time of the study. Ten subjects were taking theophylline, inhaled and/or oral fS-agonist bronchodilators, and systemic corticosteroids or had discontinued systemic corticosteroid therapy within two weeks prior to the study.  Two subjects were taking theophylline and an inhaled {3-agonist bronchodilator.