Table 2 Methodological quality of case-control studies in our meta-analyses, based on the Newcastle–Ottawa Scale.
Study | Selection (score) | Comparability (score) | Exposure (score) | ||||||
|---|---|---|---|---|---|---|---|---|---|
Adequate definition of patient cases | Representativeness of patients/cases | Selection of controls | Definition of controls | Control for important factor or additional factor | Ascertainment of exposure (blinding) | Same method of ascertainment for participants | Non-response ratea | Total scoreb | |
Migita et al.12 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 5 |
Kim et al.13 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 5 |
Chen et al.14 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 7 |
Teixeira et al.15 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 6 |
Karra et al.16 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 1 | 5 |
Bao et al.17 | 1 | 1 | 1 | 1 | 2 | 0 | 1 | 1 | 8 |
Zhang et al.18 | 1 | 1 | 1 | 1 | 2 | 0 | 1 | 1 | 8 |
Lau et al.19 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 6 |
