 - FEV1: Persistent airflow obstruction as indicated by : For participants 18 years of age at visit 1, a pre-bronchodilator FEV1 80 predicted National Health and Nutrition Examination Survey NHANES III recorded at Visit 1. For participants 12-17 years of age at Visit 1: A pre-bronchodilator FEV1 90 predicted NHANES III recorded at Visit 1 OR FEV1:FVC ratio 0.8 recorded at Visit 1 