. 2018 Aug 18;41(2):e121–e132. doi: 10.1093/pubmed/fdy138
© The Author(s) 2018. Published by Oxford University Press on behalf of Faculty of Public Health.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Fig. 2.
Key themes emerging from included studies.