Author group | Selection | Comparability | Exposure | |||||
---|---|---|---|---|---|---|---|---|
Adequae case definitin | Representativeness of the cases | Selection of Controls | Definition of Controls | Comparability of cases and controls | Ascertainm-ent of exposure | Same method of ascertainment | Non Response rate | |
AI-Qattan 2008 | 1 | 1 | – | 1 | 1 | 1 | 1 | 1 |
Mcquail 2015 [7] | – | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Rafique 2006 [19] | – | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Ridley 2017 [6] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
Terndrup 2018 [9] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |