Table 2 Newcastle–Ottawa Scale for risk of bias assessment of cohort studies included in the meta-analysis
Study | Selection | Comparability | Outcome | Overall | |||||
|---|---|---|---|---|---|---|---|---|---|
Representativeness of exposed cohort | Selection of non-exposed | Ascertainment of exposure | Outcome not present at start | Assessment of Outcome | Adequate Follow-Up Length | Adequacy of Follow-Up | |||
Huang [27] | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | 9 | |
Guo [28] | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | ☆ | 8 |
Abate [29] | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | 9 | |
Palco [30] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ☆ | 7 |