Funding for this research was provided by:
Economic and Social Research Council
Bill and Melinda Gates Foundation (OPP1106427, OPP1134076, OPP1182408, 1032350)
National Institutes of Health
Wellcome Trust (106866/Z/15/Z, 204613/Z/16/Z)
Received: 1 May 2018
Accepted: 21 November 2018
First Online: 4 December 2018
Ethics approval and consent to participate
: Ethics approval for this study was submitted and approved through the University of Southampton Ethics and Research Governance Council (ethics approval ID 26474). The data used in these analyses were obtained from the Demographic and Health Surveys (DHS) Program, which makes global health and demographic data confidentially and freely available to researchers across the world. More information on how the DHS program conducts the Informed Consent process can be found at ExternalRef removed.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.