Table II.
Study quality.
| Selection | Comparability | Exposure | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Author/(Refs.), year | Adequate definition of cases | Representativeness of case | Selection of controls | Definition of controls | Control for important factors or additional factors | Ascertainment of exposure | Same method of ascertainment for subjects | Non-response rate | Total score | |
| McNicol and Dodd (23), 1991 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 7 | |
| Masood et al (58), 1991 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 7 | |
| Rotola et al (55), 1992 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 6 | |
| Anwar et al (56), 1992 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 7 | |
| Ibrahim et al (57), 1992 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 7 | |
| Dodd et al (54), 1993 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 7 | |
| Moyret-Lalle et al (53), 1995 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |
| Suzuki et al (51), 1996 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 7 | |
| Wideroff et al (52), 1996 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 7 | |
| Anderson et al (50), 1997 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 6 | |
| Noda et al (48), 1998 | 1 | 0 | 1 | 0 | 1 | 1 | 1 | 1 | 6 | |
| Strickler et al (49), 1998 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |
| Serth et al (22), 1999 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 7 | |
| Carozzi et al (47), 2004 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 7 | |
| Leiros et al (46), 2005 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 6 | |
| Gazzaz and Mosli (45), 2009 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |
| Chen et al (6), 2011 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |
| Aghakhani et al (44), 2011 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 6 | |
| Tachezy et al (42), 2012 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 7 | |
| Salehi and Hadavi (43), 2012 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 5 | |
| Whitaker et al (43), 2013 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 1 | 6 | |
| Ghasemian et al (40), 2013 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 7 | |
| Michopoulou et al (39), 2014 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 6 | |
| Singh et al (38), 2015 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |