| Date | Event | Description |
|---|---|---|
| 19 March 2015 | New search has been performed | Review has been updated; 1 new study has been included (Tinelli 2011) |
| 19 March 2015 | New citation required but conclusions have not changed | We made no change to our conclusions at this update |
| 2 June 2008 | Amended | Review has been converted to new review format |
| 20 December 2007 | New citation required and conclusions have changed | Substantive amendments have been made |
| 20 December 2007 | New search has been performed | Review has been updated |
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