This review has been withdrawn because it has been found to be in breach of the Cochrane Commercial Sponsorship policy clause 2: 

‘Individuals who are currently employed or where employed any time in the last three years by a company that has a real or potential financial interest in the outcome of the review (including but not limited to drug companies or medical device manufacturers); or who hold or have applied for a patent related to the review are prohibited from being Cochrane Review authors. In most cases, current or previous employment would be characterized by the affiliation statement made by the author at the title registration, protocol, or review stage of the review’. 

The editorial group responsible for this previously published document have withdrawn it from publication.