 Age between 35-75 years. A smoking history of at least 10 pack years. 1 pack year 20 cigarettes per day for 1 year FEV1:FVC ratio of 0.7, post-bronchodilator FEV1 of 85 predicted, reversibility with inhaled beta2-agonist of 15 of predicted FEV1: all three criteria are required. 