Date	Event	Description
7 May 2008	Amended	Converted to new review format.
13 December 2007	New citation required and conclusions have changed	Submitted for publication in Issue 2, 2008.Substantive amendment. New contact author added. New trials included and excluded; more evidence offered and conclusions modified. Plain Language Summary authored by the Cochrane Consumer Network
27 June 2005	Amended	Contact details edited. Submitted for publication in Issue 3, 2005.
17 November 2004	Amended	Edited. Submitted for publication in Issue 1, 2005.
29 May 2001	New search has been performed	Minor update. Submitted for publication in Issue 4, 2001.
26 May 2000	New citation required and conclusions have changed	First version of the review submitted for publication in Issue 3, 2000.