| Date | Event | Description |
|---|---|---|
| 16 September 2009 | New search has been performed | New searches completed and one new study included. 'Risk of bias' tables completed. Two studies previously not classified are now excluded. |
| 27 October 2008 | Amended | Converted to new review format. |
| 14 November 2006 | New citation required and conclusions have changed | Substantive amendment. One new study included. |
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