| Date | Event | Description |
|---|---|---|
| 3 December 2013 | Amended | Text amendment |
| 29 March 2011 | New search has been performed | New search conducted in March 2009 and authors amended. |
| 29 March 2011 | New citation required but conclusions have not changed | New trials identified and included. |
| 19 April 2002 | New citation required and conclusions have changed | Substantive amendment |
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.