The US Lung Health Study.

The US Lung Health Study was a randomized clinical trial carried out in 10 clinical centres in the United States of America and Canada that enrolled 5887 male and female smokers age 35-60 years with early chronic obstructive pulmonary disease (COPD). Its purpose was to determine whether a programme incorporating smoking intervention and use of an inhaled bronchodilator (ipratropium bromide) can slow the rate of decline in the forced expiratory volume in one second (FEV1) in middle aged smokers with early COPD. Participants were randomized with equal probability into three groups: (i) smoking intervention plus bronchodilator; (ii) smoking intervention plus placebo; or (iii) no intervention. The primary outcome was rate of change and cumulative change in FEV1 over a 5 year period. The primary finding was that the use of the bronchodilator did not influence the long-term decline in FEV1. However, the aggressive smoking intervention programme significantly reduced the age-related decline in FEV1.