Contributions to present update of review

Conceiving the review: Regina Paolucci El Dib (RED)

Co‐ordinating the review: RED

Undertaking manual searches: RED

Screening search results: RED

Organising retrieval of papers: RED

Screening retrieved papers against inclusion criteria: RED and Joseph Mathew (JM)

Appraising quality of papers: RED and JM

Abstracting data from papers: RED

Writing to authors of papers for additional information: RED

Providing additional data about papers: RED

Obtaining and screening data on unpublished studies: RED

Data management for the review: RED

Entering data into Review Manager (RevMan 5.0): RED

RevMan statistical data: RED

Other statistical analysis not using RevMan: RED

Double entry of data: (data entered by person one: RED; data entered by person two: JM)

Interpretation of data: RED and JM

Statistical inferences: RED

Writing the review: RED and JM

Guarantor for the review (one author): RED

Person responsible for reading and checking review before submission: RED and JM

Contributions to original review

Regina Paolucci El Dib was responsible for the conception of this review. Regina Paolucci El Dib and Jos Verbeek were responsible for the design and overall co‐ordination of the protocol. Álvaro Nagib Atallah was responsible for co‐ordinating the protocol. Regina Paolucci El Dib and Jos Verbeek were responsible for designing the search strategy, running searches, screening search results, obtaining papers, screening retrieved papers against the inclusion criteria, appraising quality of papers and extracting data. Regina Paolucci El Dib, Jos Verbeek and Regis Bruni Andriolo wrote to authors of papers for additional information and to locate potentially relevant unpublished or ongoing studies. Regina Paolucci El Dib, Regis Bruni Andriolo and Bernardo Soares were responsible for data management in the review. Regina Paolucci El Dib and Bernardo Soares analysed and interpreted data and wrote up the results.