Date	Event	Description
2 October 2012	New search has been performed	For this update, published in Issue 11, 2012, the following changes were made: 1. The search strategies were revised and updated. 2. The search was updated to July 2012. 3. No new studies were included, six new studies were excluded and three ongoing studies were newly identified. 4. A reappraisal of the eligibility of nine previously excluded studies resulted in the deletion of seven non‐eligible studies. 5. As per Collaboration guidance, the methods were updated to assess risk of bias.
2 October 2012	New citation required and conclusions have changed	The 'Implications for research' section has been changed in light of three newly‐identified ongoing studies.