Background: The Lung Health Study (LHS), a 5-year, randomized, prospective clinical trial, studied the effects of smoking intervention and therapy with inhaled anticholinergic bronchodilators on FEV1 in participants who were 35 to 60 years of age and had mild COPD. Participants were randomized into the following three groups: usual care; smoking cessation plus inhaled ipratropium bromide; and smoking cessation plus placebo inhaler. This report evaluates the effects of these interventions, demographic characteristics, smoking status, and FEV1 changes on airway responsiveness (AR). Methods and results: Of 5,887 participants, 4,201 underwent methacholine challenge testing both at study entry and study completion. All groups increased AR during the 5-year period. The increase in AR was greatest in continuing smokers and was associated with a greater FEV1 decline. An intent-to-treat analysis indicated no significant differences in AR changes among the three groups. Conclusions: Changes in AR over a 5-year period in the LHS were primarily related to changes in the FEV1. The greater the decline in FEV1, the greater the increase in AR. Smoking cessation had a small additional benefit in AR beyond its favorable effects on FEV 1 changes.
Bibliographical noteFunding Information:
This research was supported by contracts NO1-HR46002 and NO1-46014 from the Division of Lung Diseases, National Heart, Lung, and Blood Institute, National Institutes of Health. The following pharmaceutical companies supplied drugs used in this study: Boehringer Ingelheim Pharmaceuticals, Inc, Ridgefield, CT (Atrovent and placebo inhalers); and Marion Merrell Dow Inc, Kansas City, MO (Nicorette). The Salt Lake City Center has been assisted by the Clinical Research Center, Public Health Research grant M01-RR00064 from the National Center for Research Resources.
- Airway hyperresponsiveness
- Airways reactivity
- Methacholine bronchoprovocation challenge
- Smoking cessation