| Date | Event | Description |
|---|---|---|
| 17 February 2014 | Amended | Results of updated search (December 2010, May 2012) added to review, 10 new studies added to Characteristics of included studies and one study to the Characteristics of studies awaiting classification pending update of review. |
| 30 October 2008 | Amended | Converted to new review format. |
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