1. Department of Population Health, London School of Hygiene and Tropical Medicine , London , UK
2. School of Health and Social Care, University of Essex , Colchester , UK
3. Department of Epidemiology and Public Health, University College London , London , UK
4. UCL Anthropology, University College London , London , UK
5. Bristol Medical School, University of Bristol , Bristol , UK
6. Department of Anthropology, University of Zürich , Zürich , Switzerland
7. BirthRites Lise Meitner Research Group, Max Planck Institute for Evolutionary Anthropology , Leipzig , Germany