| Date | Event | Description |
|---|---|---|
| 15 August 2008 | New citation required and conclusions have changed | Aug 2008: new author team, protocol changed and previous included studies data amended, new studies added, conclusions changed. |
| 5 May 2008 | Amended | Converted to new review format. |
| 10 September 2007 | New search has been performed | New literature search performed. |
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