Table 2 Risk of bias summary
# | Study, year | Random sequence generation (selection bias) | Allocation concealment (selection bias) | Blinding of participants and personnel (performance bias) | Blinding of outcome assessment (detection bias) | Incomplete outcome data addressed (attrition bias) | Selective outcome reporting (reporting bias) | Other bias |
|---|---|---|---|---|---|---|---|---|
1 | Dantas, 2017 [2] | Unclear | Unclear | Low | Low | Low | Low | High |
2 | Smiley, 2014 [12] | Unclear | Unclear | Low | Low | High | Low | Low |
3 | Pereira Santos, 2013 [10] | Unclear | Unclear | Unclear | Unclear | High | Low | High |
4 | Studer, 2012 [16] | Low | Unclear | Low | Unclear | High | Low | High |
5 | Esen, 2005 [17] | Unclear | Unclear | Low | Unclear | Low | Low | Low |
6 | Fong, 2005 [18] | Unclear | Unclear | Low | Low | Low | Low | Low |
7 | Ganzberg, 2005 [9] | Unclear | Unclear | Low | Unclear | Unclear | Low | Low |
8 | Jerjes, 2005 [19] | Unclear | Unclear | Low | Low | Low | Low | Low |
9 | Manani, 2004 [20] | Unclear | Unclear | Unclear | Unclear | Low | Low | Low |
10 | Leitch, 2004 [4] | Low | Unclear | Low | Unclear | Low | Low | Low |
11 | Dionne, 2001 [8] | Unclear | Unclear | Unclear | Unclear | Low | Low | Low |
12 | Bell, 2000 [21] | Low | Unclear | Unclear | Unclear | Low | Low | Low |
13 | Milgrom, 1994 [22] | Low | Unclear | Low | Unclear | Low | Low | Low |
14 | Stopperich, 1993 [23] | Unclear | Unclear | Low | Unclear | Low | Low | Low |
15 | Luyk, 1992 [24] | Unclear | Unclear | Low | Unclear | Unclear | Low | High |
16 | Luyk, 1991 [25] | Unclear | Unclear | Unclear | Unclear | High | Low | Low |
17 | O’Boyle, 1987 [26] | Low | Unclear | Low | Unclear | Low | Low | Low |