Table 3.
Levels of evidence and Newcastle–Ottawa Scale scores for case–control studies
| Study | Newcastle–Ottawa Scale | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Selection | Comparability | Exposure | Total score | ||||||
| 1 | 2 | 3 | 4 | 1 | 1 | 2 | 3 | ||
| Foucher et al. [26] | ★ | ★ | ★ | ★★ | ★ | ★ | ★★★★★★★ (7) | ||
| Lugade et al. [14] | ★ | ★ | ★ | ★ | ★★ | ★ |
★★★★★★★ (7) |
||
| Nantel et al. [27] | ★ | ★ | ★ | ★ | ★★ | ★ |
★★★★★★★ (7) |
||
| Wesseling et al. [30] | ★ | ★ | ★★ | ★ | ★ |
★★★★★★ (6) |
|||
| Foucher and Wimmer [31] | ★ | ★ | ★★ | ★ |
★★★★★ (5) |
||||
| Horstmann et al. [32] | ★ | ★ | ★★ | ★ |
★★★★★ (5) |
||||
| Naili et al. [29] | ★ | ★ | ★ | ★ | ★ |
★★★★★ (5) |
|||
| Rösler and Perka [28] | ★ | ★ | ★ | ★ | ★ |
★★★★★ (5) |
|||
Selection (maximum ★★★★): 1) Is the case definition adequate?, 2) Representativeness of the cases, 3) Selection of controls, 4) Definition of controls; Comparability (maximum ★★): 1) Comparability of cases and controls on the basis of the design or analysis; Exposure (maximum ★★★): 1) Ascertainment of exposure; 2) Cases and controls: same ascertainment method, 3) Cases and controls: same non-response date