| Table 3. Assessment of the risk of bias. | ||||||||||
| Study | Selection of exposed cohort | Selection of non-exposed cohort | Assessment of exposure |
Demonstration that outcome was not present at the start of the study | Comparability (basics) | Comparability (others) | Assessment of outcome | Length of follow up | Adequacy of follow up | Total |
|---|---|---|---|---|---|---|---|---|---|---|
| Alexander et al., 1996 |
1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 5/9 |
| Alexander et al., 1998 |
1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 5/9 |
| Bonde et al., 2014 |
1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 5/9 |
| Eibensteiner et al., 2005 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 5/9 |
| Farag et al., 2024 |
1 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 5/9 |
| Hovatta et al., 1998 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 5/9 |
| Hsu et al., 2009 |
1 | 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 5/9 |
| Kasperczyk et al., 2008 |
1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 6/9 |
| Kuo et al., 1997 |
1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 6/9 |
| Mahmoud et al., 2005 |
1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 6/9 |
| Moran-Martinez et al., 2013 |
1 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 5/9 |
| Naha and Chowdhury, 2006 |
1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 6/9 |
| Naha and Manna, 2007 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 6/9 |
| Naha et al., 2005 |
1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 6/9 |
| Saaramen et al., 1987 |
1 | 0 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 4/9 |
| Telisman et al., 2000 |
1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 6/9 |
| Wijesekara et al., 2020. |
1 | 1 | 1 | 0 | 1 | 0 | 1 | 0 | 0 | 5/9 |
Number indicates the number of stars
6-9: Low risk of bias, 4 and 5: moderate risk of bias, ≤ 3: high risk of bias