Contributions of editorial base:
Nicky Cullum: edited the protocol; advised on methodology, interpretation and protocol content.
Liz McInnes, Editor: Approved the final protocol prior to submission.
Sally Bell-Syer: coordinated the editorial process. Advised on methodology, interpretation and content. Edited the protocol.
Ruth Foxlee: designed the search strategy and edited the search methods section.
Rachel Richardson: edited the protocol.