1 Health Services Research Unit, University of Aberdeen, kirsty.loudon@abdn.ac.uk.
2 Health Services Research Unit, University of Aberdeen.
3 North York General Hospital, Toronto, ON M2K 1E1, Canada.
4 Division of Population Health Sciences, University of Dundee, Dundee DD2 4BF, UK.
5 Dalla Lana School of Public Health, University of Toronto; Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St Michael's, Toronto, Canada.
6 Centre for Studies in Family Medicine, Schulich School of Medicine & Dentistry, Western University, Western Centre for Public Health and Family Medicine, London, ON N6A 3K7, Canada.