Relevant literature was accessed using the Cochrane database, embase and PubMed on 29 October 2013. 
Cochrane database
Relevant literature was accessed using the Cochrane database, embase and PubMed on 29 October 2013. 
embase
Relevant literature was accessed using the Cochrane database, embase and PubMed on 29 October 2013. 
PubMed