Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2020 Sep 4;2020(9):CD013458. doi: 10.1002/14651858.CD013458.pub2

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

Copyright © 2020 The Authors. Cochrane Database of Systematic Reviews published by John Wiley & Sons, Ltd. on behalf of The Cochrane Collaboration.

This is an open access article under the terms of the Creative Commons Attribution Licence, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

PMC Copyright notice

Quality assessment AMSTAR 2.