Table 2.
Quality assessment of studies included in the present meta-analysis using the Newcastle–Ottawa Scale
| Study ID | Selection | Comparability | Outcome/exposure |
|---|---|---|---|
| Amorim (2007) | *** | ** | *** |
| Althuizen (2011) | *** | ** | ** |
| Begum (2012) | *** | ** | ** |
| Baker (2008) | *** | ** | ** |
| Huang (2010) | *** | ** | * |
| Krause (2010) | *** | ** | * |
| Kac (2004) | *** | ** | * |
| Koh (2013) | *** | ** | ** |
| Lowell (2010) | *** | ** | * |
| Mamum (2010) | *** | ** | ** |
| Maddah (2009) | *** | ** | ** |
| Østbye (2010) | *** | ** | ** |
| Oken (2009) | *** | ** | ** |
| Rode (2011) | *** | ** | *** |
| Rothberg (2011) | *** | ** | ** |
| Scholl (1995) | *** | ** | * |
| Walker (2004) | *** | ** | ** |