Table 3 Quality assessment according to the Newcastle–Ottawa scale of the included studies
Author | Selection | Comparability | Exposure | Total score |
|---|---|---|---|---|
Sarshekeh 2017 | 4 | 2 | 3 | 9 |
Mizuno 2018 | 4 | 2 | 3 | 9 |
Oyanagi 2019 | 3 | 2 | 2 | 7 |
Liao 2019 | 4 | 2 | 2 | 8 |
Fleming 2013 | 3 | 1 | 2 | 6 |
Jia 2017 | 3 | 2 | 3 | 8 |
Ando 2005 | 3 | 1 | 2 | 6 |
Miyaki 1999 | 3 | 2 | 2 | 7 |
Khan 2018 | 3 | 1 | 2 | 6 |
Stahler 2020 | 3 | 2 | 3 | 7 |