Article History
Received: 6 March 2019
Accepted: 29 July 2019
First Online: 11 August 2019
Compliance with ethical standards
: The study was conducted in accordance with the ethical standards laid down by the Declaration of Helsinki [CitationRef removed]. Approval for the study was granted by the University of Pretoria, Faculty of Health Sciences (ethics reference number 263/2015).
: The authors declare that they have no conflict of interest.
: Any opinions, findings, and conclusions expressed in this paper are those of the authors, and therefore, the NRF does not accept any liability in regard thereto.