| Date | Event | Description |
|---|---|---|
| 19 March 2009 | Amended | Correction to appendix |
| 6 November 2008 | New citation required and conclusions have changed | 30 studies added to the review; primary outcome substantially changed by addition of new data. |
| 29 May 2008 | New search has been performed | New search run. |
| 1 May 2008 | Amended | Converted to new review format. |
| 21 September 2000 | New citation required and conclusions have changed | Substantive amendment. |
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