Figure 4

Evidence of publication bias by Funnel plot. Funnel plot asymmetry is demonstrated by evidence of a cluster of small studies with low-protective odds ratio and the paucity of small negative studies in the lower right of the funnel plot.
Evidence of publication bias by Funnel plot. Funnel plot asymmetry is demonstrated by evidence of a cluster of small studies with low-protective odds ratio and the paucity of small negative studies in the lower right of the funnel plot.