The baseline characteristics of these 26 cohorts can be seen in Supplementary Table 1. Each cohort obtained approval from appropriate ethical/regulatory bodies; informed consent was obtained for all individuals. (Further cohort-specific methods can be found in the Data Supplement.) As most of these cohorts did not have post-bronchodilator spirometry, we used a modified definition of GOLD criteria based on pre-bronchodilator spirometry: forced expiratory volume in 1 second (FEV1) < 80% and FEV1 to forced vital capacity (FVC) ratio of < 0.7 for cases, and FEV1 > 80% and FEV1/FVC > 0.7 for controls. Logistic regression was performed in each cohort, adjusting for age, sex, pack-years of smoking, ever-smoking status, current-smoking status, and ancestry-based principal components, as appropriate for each study. Summary statistics were assessed using EasyQC55 version 10.1. More detailed cohort information, including cohort-specific methods, can be found in the Supplementary Note.
