Table 2 Newcastle Ottawa scale for assessing the risk of bias in the included studies.
Adequacy of case definition | Case representativeness | Selection of controls | Definition of controls | Comparability of groups | Ascertainment of exposure | Similarity in the method of ascertainment | Non-response rate | Total* | |
|---|---|---|---|---|---|---|---|---|---|
Akbal et al.5 | * | – | * | * | * | * | – | – | 5 |
Anetor et al.3 | – | – | * | * | * | – | * | – | 4 |
Anetor et al.6 | – | – | * | * | ** | – | * | – | 5 |
Batra et al.4 | – | – | * | – | ** | – | * | – | 4 |
Dongre et al.7 | – | – | – | – | – | – | * | – | 1 |
Estela Kristal Boneh et al.8 | – | * | * | * | – | – | * | * | 5 |
Himani et al.28 | – | – | – | – | * | – | * | – | 2 |
Mazumder et al.29 | – | – | * | * | – | – | * | – | 3 |
Osterode et al.9 | – | – | – | – | – | – | * | – | 1 |
Pizent et al.14 | – | * | * | * | * | – | * | * | 6 |
Wang et al.13 | – | – | * | * | ** | – | * | – | 5 |
