. 2014 May 20;348:g3174. doi: 10.1136/bmj.g3174
© Ford et al 2014
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 3.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/3.0/.
Fig 1 Flow diagram of assessment of studies identified in the systematic review