Table 2.
Risk of bias assessment using the Newcastle-Ottowa Scale.
| Study | Selection | Comparability | Exposure | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Case−control | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | Total |
| Abdullah et al.49 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0/9 |
| Al Imran et al.50 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0/9 |
| Ashouri et al.20 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 5/9 |
| Bishop et al.23 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 4/9 |
| Bounds et al.53 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 4/9 |
| Caza-Szoka et al.54 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 3/9 |
| Caza-Szoka et al.24 | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 3/9 |
| Chan et al.55 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 6/9 |
| Darvishi et al.25 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 4/9 |
| Du et al.57 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 6/9 |
| Hu et al.28 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 4/9 |
| Hung et al.29 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1/9 |
| Jin-Heeku et al.32 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0/9 |
| LeDuff et al.34 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2/9 |
| Melo Riveros et al.40 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 3/9 |
| Oliver et al.41 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 4/9 |
| Oliver et al.42 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 4/9 |
| Olugbade et al.62 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0/9 |
| Parsaeian et al44. | 0 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 4/9 |
| Sandag et al.63 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0/9 |
| Silva et al.47 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2/9 |
| Ung et al.64 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 6/9 |
| Karabulut et al.58 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0/9 |
| Mathew et al.38 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 0 | 3/9 |
| Mathew et al.61 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 5/9 |
| Vaughn et al.65 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 5/9 |
| Vaughn et al.66 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 5/9 |
| Vaughn et al.48 | 0 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 1 | 5/9 |
| Sari et al.45 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 1 | 2/9 |
| Cohort | Selection | Comparability | Outcome | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Magnusson et al.37 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 6/9 |
| Azimi et al.21 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 6/9 |
| Azimi et al.22 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 5/9 |
| Barons et al.52 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 6/9 |
| Hallner et al.27 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 0 | 6/9 |
| Jarvik et al.30 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 7/9 |
| Jiang et al.31 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 1 | 1 | 5/9 |
| Shamim et al.46 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 5/9 |
| Othera | Selection | Comparability | Outcome | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Kadhim et al.33 | — | — | — | — | — | — | — | — | — | — |
| Lee et al.19 | — | — | — | — | — | — | — | — | — | — |
| Lin et al.60 | — | — | — | — | — | — | — | — | — | — |
| Andrei et al.51 | — | — | — | — | — | — | — | — | — | — |
| Li et al.59 | — | — | — | — | — | — | — | — | — | — |
| Dickey et al.56 | — | — | — | — | — | — | — | — | — | — |
| Liszka-Hackzell et al.35 | — | — | — | — | — | — | — | — | — | — |
| Liszka-Hackzell et al.36 | — | — | — | — | — | — | — | — | — | — |
| Meier et al.39 | — | — | — | — | — | — | — | — | — | — |
| Gal et al.26 | — | — | — | — | — | — | — | — | — | — |
| Oude et al.43 | — | — | — | — | — | — | — | — | — | — |
Higher scores indicate better quality.
aNeither case−control nor cohort study design.