Fig. 5
![Fig. 5](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs12883-020-01654-y/MediaObjects/12883_2020_1654_Fig5_HTML.png)
Meta-regression of the relationship between the study year and the studies included in the meta-analysis using the standardized mean difference index before and after the intervention
Meta-regression of the relationship between the study year and the studies included in the meta-analysis using the standardized mean difference index before and after the intervention