Date	Event	Description
6 November 2019	Amended	Correction made to the risk of bias assessment for Govaert 1994a. In the 'Characteristics of included studies' for Govaert 1994a, the authors' judgement for each bias in the risk of bias table was marked as "unclear" in error. This error was introduced in the 2018 version of the review (https://doi.org/10.1002/14651858.CD004876.pub4) and has now been corrected to "low" for each bias, as in earlier versions of this review.
31 December 2016	New citation required but conclusions have not changed	Our conclusions remain unchanged.
31 December 2016	New search has been performed	We updated our searches for randomised trials conducted. We did not identify any new trials for inclusion or exclusion.
20 January 2010	New search has been performed	Searches conducted. We identified 18 potential trials. We included four new trials, two case‐control studies (Jordan 2007; Puig‐Barbera 2007), and two cohort studies (Hara 2006; Leung 2007). We excluded 13 new trials (Castilla 2006; Garcia‐Garcia 2009; Hara 2008; Isahak 2007; Landi 2006; Manzoli 2007; Moreno 2009; Nichol 2007; Ortqvist 2007; Skull 2009; Tsai 2007; van Vuuren 2009; Voordouw 2006). One excluded trial was formerly awaiting classification (Vila‐Corcoles 2005).
20 January 2010	New citation required and conclusions have changed	Three new authors (EF, LAA, ST) joined the review team, while previous authors no longer contributed to this update. Our conclusion changed in part. This was due both to a re‐evaluation of the whole topic and to ambiguity in the previous text which readers found confusing.
8 May 2008	Amended	Converted to new review format
25 July 2007	Feedback has been incorporated	Feedback comment and reply added to review.
24 May 2006	New search has been performed	Searches conducted.