| Date | Event | Description |
|---|---|---|
| 13 June 2013 | New citation required but conclusions have not changed | Our conclusions remain unchanged. |
| 13 June 2013 | New search has been performed | Searches updated. No new studies were identified for inclusion or exclusion. |
| 5 August 2010 | Amended | Contact details updated. |
| 12 November 2008 | New search has been performed | Searches conducted. No new trials identified. |
| 27 July 2008 | Amended | Converted to new review format. |
| 5 June 2006 | New search has been performed | Searches conducted. No new trials identified. |
| 9 July 2004 | New search has been performed | Searches conducted. |
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