Zubia Mumtaz1, George T H Ellison2, Alyssa Ferguson3, Sarah Salway4. 1. School of Public Health, Edmonton Clinic Health Academy, University of Alberta, Edmonton, AB T6G 1C9, Canada. Electronic address: zmumtaz@ualberta.ca. 2. Centre for Anthropological Research, University of Johannesburg, Johannesburg, South Africa; School of Medicine, University of Leeds, Leeds, UK. 3. School of Public Health, Edmonton Clinic Health Academy, University of Alberta, Edmonton, AB T6G 1C9, Canada. 4. School of Health and Related Research, University of Sheffield, Sheffield, UK.