Statistics from Altmetric.com
Contributors TB, IL, NS and ME conceived the study. TB performed the study. IL performed the statistical analysis. TB wrote the paper. All authors approved the final draft.
Competing interests None declared.
Ethics approval Ethical approval was granted from the University of Cape Town Human Research Ethics Committee. Reference 192/2016.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement Requests for data sharing should be directed to the corresponding author.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.