Table 2.
Newcastle–Ottawa Scale for the quality assessment of case–control studies
| Study | Selection | Comparability | Exposure | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Definition of exposure | Representativeness | Selection of controls | Definition of controls | On age | On other risk factors | Assessment of exposure | Same methods of ascertainment for cases and controls |
Nonresponse rate | ||
| Aamir, 2008 [14] | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 8 |
| Al-Balbeesi, 2011 [20] | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 8 |
| Alpay, 2013 [21] | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 1 | 1 | 6 |
| Cebeci, 2006 [15] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Cho, 2013 [28] | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 1 | 1 | 5 |
| Confino-Cohen, 2012 [12] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Czarnecka-Operacz, 2017 [16] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Diaz Angulo, 2015 [13] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Ghaffari, 2013 [22] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Kasumagic-Halilovic, 2017 [17] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Leznoff, 1983 [6] | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 0 | 5 |
| Magen, 2016 [18] | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Nuzzo, 2011 [19] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Okba, 2015 [23] | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Ryhal, 2001 [8] | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 7 |
| Turktas, 1997 [24] | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Verneuil, 2004 [25] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Wan, 2013 [26] | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Yadav, 2013 [27] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |