Table 4.
Quality of included studies as assessed with the Newcastle–Ottawa Quality Assessment Scale for Cohort Studies14*
| Study | Selection | Comparability | Outcome | ||||
|---|---|---|---|---|---|---|---|
|
|
|
||||||
| Representativeness of exposed cohort | Selection of nonexposed cohort | Ascertainment of exposure | Assessment of outcome | Duration of follow-up | Completeness of follow-up | ||
| John et al., 201011 | ★ | ★ | ★ | ★★ | ★ | ★ | ★ |
|
| |||||||
| Kumar et al., 201217 | |||||||
|
| |||||||
| Maltais et al., 201418 | ★ | ★ | ★ | ★★ | ★ | ★ | ★ |
|
| |||||||
| Nishi et al., 201420 | ★ | ★ | ★ | ★ | |||
|
| |||||||
| Segura et al., 201519 | ★ | ★ | ★ | ★ | |||
|
| |||||||
| Tsiouris et al., 201312 | ★ | ★ | ★ | ★ | ★ | ★ | ★ |
|
| |||||||
| Yoshioka et al., 201421 | ★ | ★ | ★ | ★ | |||
*
A study can be awarded a maximum of 1 star for each item within the “Selection” and “Outcome” categories. A maximum of 2 stars can be given for “Comparability.”