Table 2.
Quality Assessment of Included Studies
| Study | Case defined with independent validation | Representativeness of the cases | Selection of controls from community | Statement that controls have no history of outcome | Cases and controls matched and/or adjusted by factors | Ascertain exposure by blinded structured interview | Same method of ascertainment for cases and controls | Same response rate for both groups | Overall score |
|---|---|---|---|---|---|---|---|---|---|
| Arusoglu, 2013 | 1 | 1 | 0 | 1 | 2 | 0 | 1 | 1 | 7 |
| Bideci, 2008 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 5 |
| Cassar, 2014 | 1 | 1 | 1 | 1 | 2 | 0 | 1 | 1 | 8 |
| Daghestani, 2011 | 1 | 0 | 1 | 1 | 2 | 0 | 1 | 1 | 7 |
| Houjeghani, 2011 | 1 | 1 | 1 | 1 | 2 | 0 | 1 | 1 | 8 |
| Japur, 2014 | 1 | 1 | 0 | 1 | 2 | 0 | 1 | 1 | 7 |
| Kale-Gurbuz, 2013 | 1 | 1 | 1 | 0 | 2 | 0 | 1 | 1 | 7 |
| Mahde, 2009 | 1 | 0 | 0 | 0 | 2 | 0 | 1 | 1 | 5 |
| Micic, 2007 | 1 | 0 | 0 | 1 | 2 | 0 | 1 | 1 | 6 |
| Mitkov, 2008 | 1 | 1 | 0 | 1 | 2 | 0 | 1 | 1 | 7 |
| Moran, 2007 | 1 | 1 | 1 | 0 | 2 | 0 | 1 | 1 | 7 |
| Orio, 2003 | 1 | 0 | 0 | 1 | 2 | 0 | 1 | 1 | 6 |
| Ozgen, 2010 | 1 | 0 | 0 | 0 | 2 | 0 | 1 | 1 | 5 |
| Panidis, 2005 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 5 |
| Panidis, 2010 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 5 |
| Schöfl, 2002 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 5 |
| Shi, 2011 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 5 |
| Temel, 2010 | 1 | 0 | 1 | 1 | 2 | 0 | 1 | 1 | 7 |
| Wasko, 2004 | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 1 | 5 |
| Zwirska-Korczala, 2008 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 7 |
1 means study adequately fulfilled a quality criterion (2 for case-control fully matched and adjusted), 0 means it did not. Quality scale does not imply that items are of equal relevant importance