| Date | Event | Description |
|---|---|---|
| 25 February 2016 | New search has been performed | Search updated. No new included studies. New data from previously included study added. Seven new studies excluded. Two new ongoing studies added. |
| 25 February 2016 | New citation required but conclusions have not changed | Search updated. No new included studies. Seven new studies excluded. Two new ongoing studies added. New data from previously included study added. Text amended to reflect current Cochrane policy. 'Summary of findings' table added. |
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