Date	Event	Description
20 December 2019	New citation required but conclusions have not changed	Following correspondence between the authors and one of the peer reviewers post‐publication, the authors have revised some of the risk of bias judgements. Some terminology around confounding has also been changed.
20 December 2019	Amended	Following correspondence between the authors and one of the peer reviewers post‐publication, the authors have revised some of the risk of bias judgements. Some terminology around confounding has also been changed.