1. Dalhousie University; Departments of Pediatrics and Obstetrics & Gynaecology; Halifax NS Canada
2. University Medical Centre of the Johannes Gutenberg University; Division of Paediatric Epidemiology, Institute of Medical Biostatistics, Epidemiology and Informatics (IMBEI); Langenbeckstrausse 1 Mainz Rhineland-Palatinate Germany 55131
3. Dalhousie University & IWK Health Centre; Departments of Pediatrics, Community Health & Epidemiology; G-2214, 5850/5980 University Avenue Halifax Nova Scotia Canada B3K 6R8