Fig. 2

Risk of bias summary: review authors' judgements about each risk of bias item for each included study. Green ( −): Low risk of bias, Red ( −): High risk of bias, Yellow (?): unclear risk of bias
Risk of bias summary: review authors' judgements about each risk of bias item for each included study. Green ( −): Low risk of bias, Red ( −): High risk of bias, Yellow (?): unclear risk of bias