You have landed on a page of the archived Cochrane Community website. This site is not being maintained or updated.
If you are looking for Cochrane Review evidence, please visit Cochrane’s evidence page.
If you are a Cochrane contributor looking for Community resources, please visit the new Cochrane Community website.
To browse Podcasts by topic, please visit the new Cochrane Summaries site here
This Review was updated in February 2011. Please refer to the updated Review here as this Podcast may no longer be accurate.
You are missing some Flash content that should appear here! Perhaps your browser cannot display it, or maybe it did not initialize correctly.
Comments for improvement or correction are welcome.Email: firstname.lastname@example.org