Table 2 Results of quality assessment using the Newcastle-Ottawa Scale for case-control studies
Study | Selection | Comparability Control for important factor | Exposurer | Scores | |||||
|---|---|---|---|---|---|---|---|---|---|
Adequate definition of cases | Representat-iveness of the cases | Selection of controls | Definition of controls | Ascertainment of exposure | Same method of ascertainment cases and controls | Nonresponse rate | |||
Erbay 2006 | ★ | ★ | ✩ | ★ | ★✩ | ★ | ★ | ★ | 7 |
Lorenzoni 2008 | ★ | ★ | ✩ | ★ | ★★ | ★ | ★ | ★ | 8 |
Miller 2009 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 9 |
Chun-Cheng 2009 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 9 |
Ni 2009 | ★ | ★ | ✩ | ★ | ★✩ | ★ | ★ | ★ | 7 |
Han-bing 2010 | ★ | ★ | ✩ | ★ | ★✩ | ★ | ★ | ★ | 7 |
Zhou 2011 | ★ | ★ | ✩ | ★ | ★✩ | ★ | ★ | ★ | 7 |
Cha 2011 | ★ | ★ | ✩ | ★ | ★★ | ★ | ★ | ★ | 8 |
Zeng 2013 | ★ | ★ | ★ | ★ | ★✩ | ★ | ★ | ★ | 8 |
Antonini 2014 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | ★ | 9 |
Docampo 2015 | ★ | ★ | ★ | ★ | ★✩ | ★ | ★ | ★ | 8 |
Maarbjerg 2015 | ★ | ★ | ✩ | ★ | ★★ | ★ | ★ | ★ | 8 |
Hughes 2019 | ★ | ★ | ✩ | ★ | ★★ | ★ | ★ | ★ | 8 |