Funding for this research was provided by:
Albert-Ludwigs-Universität Freiburg im Breisgau
Article History
Accepted: 5 November 2021
First Online: 2 December 2021
Declarations
:
: No sources of funding were used to assist in the preparation of this article.
: John Dick Fleming, Ramona Ritzmann and Christoph Centner declare that they have no conflicts of interest relevant to the content of this review.
: The datasets generated and analyzed during the current systematic review and meta-analysis are available from the corresponding author upon reasonable request.
: Not applicable.
: JF, RR and CC conceived the study. JF and CC completed the study protocol and registration. JF, RR and CC completed the database searches and extraction. JF and CC completed the title and abstract screening. JF and CC completed the full-text review. JF and CC completed the risk-of-bias assessment. JF and CC completed the data extraction. JF and CC completed the data analysis. JF drafted the Introduction and Methods sections, and RR and CC drafted the Results and Discussion sections. All authors reviewed, revised and approved the final manuscript.