Fig. 2

Estimated risk of bias across all studies. Risk-of-bias summary and graph with detailed assessments using the Cochrane Collaboration tool. Each domain was judged as high, low, or unclear risk of bias with the overall assessment of each study graded as low risk of bias (when more than five domains were low risk of bias), high risk of bias (at least three domains were high risk of bias), or medium risk of bias (otherwise). Because most of the included studies were well-designed RCTs, most of them were assessed as low risk of bias