1. Menzies School of Health Research, Charles Darwin University, Darwin, Australia
2. Department of Emergency Medicine, University Health Network, University of Toronto, Toronto, Canada
3. Department of Family and Community Medicine, University of Toronto, Toronto, Canada
4. Centre for Midwifery, Child and Family Health, Faculty of Health, University of Technology Sydney, Ultimo, NSW, Australia
5. Bixby Center for Population Health and Sustainability, School of Public Health, University of California, Berkeley, CA, USA