. 2018 Nov 5;147:e36. doi: 10.1017/S0950268818002947
© The Author(s) 2018
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Fig. 2.
PRISMA flow diagram describing the study design.