Table 2 The Newcastle-Ottawa Scale (NOS) used for evaluating the risk of bias within Studies
First Author, Date | Quality evaluation | Representativeness of exposed cohort | Selection of non- exposed cohort | Ascertainment of exposure | Outcome not present before study | Comparability | Assessment of outcome | follow-up long enough | Adequacy of Follow Up |
|---|---|---|---|---|---|---|---|---|---|
Jia (2013) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
Supic (2018) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
Zheng(2016) | 7 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 |
Jia (2014) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
Li (2009) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
Kawakita(2014) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
Maruyama (2018) | 7 | 1 | 0 | 1 | 0 | 2 | 1 | 1 | 1 |
Xie (2016) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
Berania(2017) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
Jia (2015) | 7 | 1 | 1 | 1 | 0 | 2 | 1 | 0 | 1 |
W. Chen (2019) | 8 | 1 | 1 | 1 | 0 | 2 | 1 | 1 | 1 |
S. Chen (2019) | 7 | 1 | 1 | 1 | 0 | 2 | 1 | 0 | 1 |