1 Respiratory Diseases Unit, Department of Medicine and Surgery, University of Milan-Bicocca Fondazione IRCCS San Gerardo, Monza, Italy;, Division of Pulmonary Medicine, Department of Medicine, University of Alberta and Alberta Health Services, Edmonton, AB.
2 Division of Pulmonary Medicine, Department of Medicine, University of Alberta and Alberta Health Services, Edmonton, AB.
3 Alberta Respiratory Centre and Division of Pulmonary Medicine, Department of Medicine, University of Alberta, Edmonton, AB, Canada.