Table 3.
Risk of bias assessment using the Newcastle–Ottawa Quality Assessment Scale.
| References | Selection (Max. ****) | Comparability (Max. **) | Outcome (Max. ***) | Total number of starsb |
|---|---|---|---|---|
| Adami Dehkordi et al. (40)a | *** | ** | ***** | |
| Andersson et al. (41) | ** | * | *** | |
| Durai et al. (42)a | *** | ** | * | ****** |
| Gerber et al. (43) | * | ** | *** | |
| Langguth et al. (44) | ** | * | *** | |
| McCormack et al. (45) | *** | *** | ||
| Meric et al. (46) | ** | ** | * | ***** |
| Salviati et al. (47) | ** | * | *** | |
| Strumila et al. (48) | ** | * | *** | |
| Weber et al. (49) | ** | * | *** | |
| Welch and Dawes (50) | *** | ** | ***** |
a
Newcastle–Ottawa Quality Assessment Scale for case-control studies was used.
b
A maximum of nine stars could be earned in total and implies the lowest Risk of Bias.