Methodologic Quality of Studies, Based on the Newcastle-Ottawa Scale (N = 11)
| Selection | Comparability | Exposure | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Study | Adequate Definition of Cases | Representativeness of Cases | Selection of Controls | Definition of Controls | Control for Important Factor or Additional Factor | Ascertain ment of Exposure (Blinding) | Same Method of Ascertainment for Subjects | Nonresponse Rate | Total Scorea |
| a Possible total scores range from 0 (lowest quality) to 9 (highest quality). Studies included in the meta-analysis were defined as high-quality if their total score was greater than 7. | |||||||||
| Case-control (n=8) | |||||||||
| Grisso et al,49 1997 | 1 | 0 | 0 | 0 | 2 | 0 | 1 | 0 | 4 |
| Vestergaard et al,39 2006 | 0 | 1 | 1 | 0 | 2 | 0 | 1 | 1 | 6 |
| Yang et al,22 2006 | 0 | 1 | 1 | 0 | 2 | 0 | 1 | 1 | 6 |
| Kaye and Jick,42 2008 | 0 | 1 | 1 | 1 | 2 | 0 | 1 | 1 | 7 |
| Targownik et al,23 2008 | 0 | 1 | 1 | 1 | 2 | 0 | 1 | 1 | 7 |
| Corley et al,50 2010 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 |
| Chiu et al,53 2010 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 |
| Pouwels et al,52 2011 | 0 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 8 |
| Cohort (n=3) | |||||||||
| Yu et al,40 2008 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 0 | 7 |
| Roux et al,41 2009 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 8 |
| Gray et al,51 2010 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 0 | 8 |