| Date | Event | Description |
|---|---|---|
| 15 August 2008 | Amended | Converted to new review format. |
| 3 September 2007 | New search has been performed | Literature search re‐run; no new studies identified. |
| 1 September 2006 | New search has been performed | Literature searches re‐run; no new studies found |
| 24 October 2000 | New citation required and conclusions have changed | Substantive amendment |
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