1 Adult Cystic Fibrosis Program, Department of Respirology, St. Michael's Hospital, Toronto, Ontario, Canada. Electronic address: chinmel@smh.ca.
2 Program in Genetics and Genome Biology, The Hospital for Sick Children Research Institute, Toronto, Ontario, Canada; Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada. Electronic address: lisa.strug@utoronto.ca.
3 Adult Cystic Fibrosis Program, Department of Respirology, St. Michael's Hospital, Toronto, Ontario, Canada; Department of Medicine, University of Toronto, Toronto, Canada. Electronic address: stephensona@smh.ca.