1Division of Pediatric Allergy and Clinical Immunology, Department of Pediatrics, McGill University Health Center, Montreal, Quebec, Canada, E-mail: ann.clarke@mcgill.ca
2Division of Clinical Epidemiology, Department of Medicine, McGill University Health Center, Montreal, Quebec, Canada, E-mail: ann.clarke@mcgill.ca
3Division of Allergy and Clinical Immunology, Department of Medicine, McGill University Health Center, Montreal, Quebec, Canada, E-mail: ann.clarke@mcgill.ca
4Lady Davis Institute for Medical Research and Jewish General Hospital, Departments of Psychiatry, Neurology and Neurosurgery, and Psychology, McGill University, Montreal, Quebec, Canada, E-mail: ann.clarke@mcgill.ca