Results of the search
There were 1621 publications identified from the initial search of
databases. From this list, 169 full articles were retrieved for closer
inspection. After examining the full articles, 47 additional articles
were identified fromthe bibliographies and also retrieved for closer
inspection (216 in total). Fromthese full articles, five were deemed
eligible for inclusion. An update search run in June 2009 did not
identify any new studies for inclusion in the review.