Date	Event	Description
2 July 2020	New citation required but conclusions have not changed	No new studies were identified for inclusion at this update.
8 May 2020	New search has been performed	Review updated to reflect current formatting of Cochrane Reviews and updated search.
9 November 2015	New citation required but conclusions have not changed	No changes to conclusions of this review.
9 November 2015	New search has been performed	Two new studies (Kesim 2008; Omar 2010) and a follow up of two previously included studies (Chan 2007; Gardner 2000) were identified for inclusion in this update.
20 September 2010	Amended	Contact details updated. New RCT included into review.
6 November 2008	Amended	Converted to new review format.
26 April 2007	New citation required and major changes	Substantive amendment