Funding for this research was provided by:
Research Council of Norway (248121, 223269)
Received: 16 April 2019
Accepted: 28 October 2019
First Online: 21 December 2019
Ethics approval and consent to participate
: This study is part of the ongoing approved RISE study. The RISE proposal including our study was approved by the University of Zambia Biomedical Research Ethics Committee (UNZABREC) on 7th September, 2015 (ethics reference number is: 021–06-15) and the Regional Ethics Committee of Western Norway (REK-Vest). All the participants gave written consent to participate.
: Not applicable.
: The authors declare that they have no competing interests.