Methodological quality of included studies
| Study | Study design | Risk of bias | Inconsistency | Indirectness | Imprecision | Other considerations | Grade |
|---|---|---|---|---|---|---|---|
| Kessler and Käfer24 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Aranda Villalobos et al31 | Observational study | Not serious | Not serious | Not serious | Not serious | None | Low |
| Nankaku et al26 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Slaven28 | Observational study | Not serious | Not serious | Not serious | Not serious | None | Low |
| Moran et al25 | Observational study | NA | Not serious | Not serious | Not serious | Strong association | Moderate |
| Stevens et al30 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Wang et al32 | Observational study | Not serious | Not serious | Not serious | Not serious | None | Moderate |
| Dowsey et al20 | Observational study | Serious | Not serious | Not serious | Not serious | Strong association | Low |
| Judge et al33 | Observational study | Not serious | Not serious | Not serious | Not serious | Very strong association | High |
| Bergschmidt et al17 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Jones et al22 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Smith et al29 | Observational study | Not serious | Not serious | Serious | Not serious | Strong association | Moderate |
| Judge et al23 | Observational study | Not serious | Not serious | Not serious | Not serious | Very strong association | High |
| Bischoff et al18 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Gandhi et al21 | Observational study | Serious | Not serious | Not serious | Not serious | None | Low |
| Nilsdotter et al27 | Observational study | Not serious | Serious | Not serious | Not serious | Strong association | Low |
| Davis et al19 | Observational study | Not serious | Not serious | Not serious | Not serious | Very strong association | High |
| Hamilton et al35 | Observational study | Not serious | Not serious | Not serious | Not serious | None | Low |
| Quintana et al37 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Nilsdotter and Lohmander36 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Dowsey et al34 | Observational study | Not serious | Not serious | Not serious | Not serious | Very strong association | High |
| Lavernia, 201138 | Observational study | Serious | Not serious | Not serious | Not serious | Strong association | Low |
| Mahomed et al39 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Vogl et al43 | Observational study | Not serious | Serious | Not serious | Not serious | NA | Low |
| Clement et al42 | Observational study | Not serious | Not serious | Not serious | Not serious | Very strong association | High |
| Johansson et al40 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Fortin et al41 | Observational study | Not serious | Not serious | Not serious | Serious | Strong association | Low |
| Badura-Brzoza et al44 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Holstege et al46 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Schafer et al47 | Observational study | Not serious | Not serious | Not serious | NA | Strong association | Low |
| Graves et al48 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
| Lavernia, 201449 | Observational study | Not serious | Not serious | Not serious | NA | None | Low |
| Lavernia et al45 | Observational study | Not serious | Not serious | Not serious | Not serious | Strong association | Moderate |
High: true effect lies close to the estimate of the effect.
Moderate: true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different.
Low: true effect may be substantially different from the estimate of effect.
Very low: true effect is likely to be substantially different from the estimate of effect.
GRADE, Grading Recommendations Assessment Development and Evaluation; NA, not applicable.