“…5,6,19,27,47 In the domain of "Completeness of data," 5 studies were evaluated as having a low risk of bias, 1,5,6,26,47 5 studies with a moderate risk of bias, 9,10,16,22,43 and 5 studies with a serious risk of bias. 19,27,50,52,54 In the domain of "Measurement instrument," 14 studies were evaluated as having a low risk of bias, 1,6,10,11,17,19,22,26,27,43,47,50,52,54 whereas one study had a moderate risk of bias. 5 In the domain of "Data analysis," 13 studies were evaluated as having a low risk of bias, 1,9,11,17,19,22,26,27,43,47,50,52,54 whereas 2 studies had a serious risk of bias.…”