University of Pittsburgh - Department of Human Genetics, University of British Columbia (UBC) - Division of Respiratory Medicine, University of Calgary - Division of Respiratory Medicine, University of British Columbia (UBC) - Division of Respiratory Medicine, University of Saskatchewan, McGill University - Division of Respiratory Medicine, affiliation not provided to SSRN, University of Toronto, McMaster University, Medical University of South Carolina, University of Pittsburgh - Department of Environmental and Occupational Health, University of Pittsburgh, University of Pittsburgh, University of Pittsburgh - Department of Medicine and Pulmonary and Critical Care Medicine, University of Pittsburgh, University of British Columbia (UBC) - Division of Respiratory Medicine and University of Pittsburgh - Medical Center (UPMC)