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. 2015 Nov 6;94(44):e1910. doi: 10.1097/MD.0000000000001910

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Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

This is an open access article distributed under the Creative Commons Attribution-NoDerivatives License 4.0, which allows for redistribution, commercial and non-commercial, as long as it is passed along unchanged and in whole, with credit to the author. http://creativecommons.org/licenses/by-nd/4.0

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The flow diagram of the study selection. The study selection including the flow of the process for identifying potentially eligible trials and the reasons for inclusion and exclusion has been represented. We have followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement for our study. From 3564 articles, 122 full-text articles were assessed eligible for this meta-analysis. After strictly considering the inclusion and exclusion criteria, 22 articles were finally selected for this systematic review and meta-analysis. PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses.