Received: 7 December 2018
Accepted: 29 April 2019
First Online: 14 May 2019
Ethics approval and consent to participate
: The study was approved by the Committee of Research and Postgraduate Studies, Faculty of Medicine and Health Science, Aden University (i.e. ethics committee for all research in health faculties in Aden). The ethics committee approved the procedure for verbal consent. Verbal consent was attained from all participants after explaining the purposes, significance and advantages of the research by the trained data collector and through a covering letter provided to each respondent. They were assured that all the gathered information would be kept private and used only for the purpose of the study. They were also informed that they had the right to withdraw from the study at any time.
: Not applicable.
: The authors declare that they have no competing interests.
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