| Date | Event | Description |
|---|---|---|
| 20 September 2010 | New search has been performed | Substantive update September 2010 ‐ 5 new trials included. Risk of bias assessment on all included studies. Minor changes to the objectives ‐ hypotheses deleted |
| 7 November 2008 | Amended | Converted to new review format. |
| 26 May 2004 | New citation required and conclusions have changed | Substantive amendment |
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