| References | Risk of bias domains a | Tier b | |||||
|---|---|---|---|---|---|---|---|
| Exposure KEY | Outcome KEY | Confounding KEY | Inappropriate selection | Attrition | Other sources of bias/statistics | ||
| Melhus et al. ( 1998 ) | + | ++ | – – | ++ | ++ | + | 2 |
| Feskanich et al. ( 2002 ) | ++ | ++ | + | ++ | ++ | + | 1 |
| Michaëlsson et al. ( 2003 ) | NR | + | NR | –– | ++ | + | 2 |
| Lim et al. ( 2004 ) | + | – | + | + | – | + | 2 |
| White et al. ( 2006 ) | – | + | – | + | – | –– | 3 |
| Key et al. ( 2007 ) | + | – | + | + | –– | + | 2 |
| Caire‐Juvera et al. ( 2009 ) | ++ | + | ++ | ++ | ++ | + | 1 |
| Rejnmark et al. ( 2004 ) | + | ++ | ++ | ++ | NR | + | 1 |
| Barker et al. ( 2005 ) | + | ++ | – | NR | + | – | 2 |
| de Jonge et al. ( 2015 ) | + | ++ | + | ++ | ++ | + | 1 |
| Toraishi et al. ( 2021 ) | + | – | – – | – | ++ | – | 3 |
| Hayhoe et al. ( 2017 ) | + | + | + | ++ | ++ | ++ | 1 |
a
Expert judgement was translated into a rating scale for each question to be answered as follows: (++): definitely low RoB; (+): probably low RoB; (NR): not reported; (−): probably high RoB; (− −): definitively high RoB.
b
The individual rating for each question was combined by an algorithm and translated to an overall tier of reliability for each individual study (RoB tier 1: low RoB; RoB tier 2: moderate RoB; RoB tier 3: high RoB).