Table 1 Newcastle-Ottawa Scale for risk of bias assessment of studies included in the meta-analysis
Study | Selection | Comparability | Outcome | Overall | |||||
|---|---|---|---|---|---|---|---|---|---|
Representativeness of exposed cohort | Selection of nonexposed | Ascertainment of exposure | Outcome not present at start | Assessment of outcome | Adequate follow-up length | Adequacy of follow-up | |||
Mladenov (3) | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 8 |
Tutino (19) | ★ | ★ | ★ | ★ | ★ | ★ | ☆ | ★ | 7 |
Omar (20) | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ☆ | 7 |
Creta (21) | ★ | ★ | ★ | ★ | ★ | ★ | ☆ | ★ | 7 |
Anheuser (7) | ★ | ★ | ★ | ★ | ☆ | ☆ | ★ | ☆ | 5 |
Thrane (22) | ★ | ★ | ★ | ★ | ★ | ☆ | ★ | ☆ | 6 |
Devaney (23) | ★ | ★ | ★ | ☆ | ☆ | ★ | ☆ | ★ | 5 |
Hung (24) | ★ | ★ | ★ | ★ | ☆ | ★ | ★ | ★ | 7 |
Li (25) | ★ | ★ | ★ | ☆ | ☆ | ★ | ★ | ☆ | 5 |
Shaw (26) | ★ | ★ | ★ | ★ | ☆ | ★ | ★ | ☆ | 6 |
Chai (27) | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 9 |
Massey (28) | ★ | ★ | ☆ | ★ | ☆ | ★ | ☆ | ★ | 5 |
Hassan (29) | ★ | ★ | ★ | ★ | ★ | ★ | ☆ | ☆ | 6 |
Mehl (30) | ★ | ★ | ☆ | ★ | ☆ | ★ | ★ | ☆ | 5 |
George (31) | ★ | ★ | ★ | ★ | ☆ | ★ | ★ | ☆ | 6 |
Krenk (32) | ★ | ★ | ☆ | ★ | ☆ | ☆ | ★ | ★ | 5 |
Steven (33) | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 8 |
Wilkinson (34) | ★ | ☆ | ★ | ★ | ☆ | ★ | ★ | ☆ | 5 |
Dahm (35) | ★ | ★ | ★ | ☆ | ★ | ☆ | ★ | ★ | 6 |
Hollabaugh (36) | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 8 |
Shupak (37) | ★ | ★ | ★ | ★ | ☆ | ★ | ★ | ★ | 7 |
Brown (38) | ★ | ★ | ★ | ★ | ☆ | ★ | ★ | ☆ | 6 |
Riseman (39) | ★ | ★ | ★ | ★ | ★ | ★ | ☆ | ★ | 7 |