Received: 3 September 2018
Accepted: 12 June 2019
First Online: 8 July 2019
Ethics approval and consent to participate
: This trial was conducted according to the guidelines laid down in the Declaration of Helsinki. Ethical approval on all procedures was obtained from the Institutional Review Board of the Faculty of Medicine at Justus Liebig University, Giessen, Germany (14 November 2014, Identifier: 198/14) and the National Ethics Committee for Health Research at the Ministry of Health, Phnom Penh, Cambodia (29 December 2014, Identifier: 0363 NECHR). Written informed consent was collected from all subjects. Participants were informed that they could leave the study at any time.
: Not applicable.
: The authors declare that they have no competing interests.