1. Department of Non-communicable Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
2. Centre for Fertility and Health, Norwegian Institute of Public Health, Oslo, Norway
3. Department of Population Health, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
4. Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, UK
5. Centre for Global Health, Usher Institute, University of Edinburgh, Edinburgh, UK