| Date | Event | Description |
|---|---|---|
| 1 October 2015 | New search has been performed | Updated 2015, seven new studies added and text updated |
| 1 October 2012 | New citation required and conclusions have changed | Three new included studies added, meta‐analysis conducted, conclusions changed (pooled effect statistically significant) |
| 1 October 2012 | New search has been performed | Updated 2012, three new studies added and text updated |
| 15 July 2008 | Amended | Converted to new review format. |
| 5 September 2006 | New citation required and conclusions have changed | Substantive amendment |
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