Fig. 2: PRISMA study flow chart.

From the 213 studies included in this SR, 192 could be used for meta-analyses. The difference (n = 21) stems from incomplete outcome data that prevented us from including some papers into the meta-analyses.

From the 213 studies included in this SR, 192 could be used for meta-analyses. The difference (n = 21) stems from incomplete outcome data that prevented us from including some papers into the meta-analyses.