Table 2.
Quality assessment of included studies based upon the Newcastle-Ottawa Scale (NOS).
| Item/Study | Luca M | Masaharu H | Mohammad H | Kentaro O | Tamandani D | Vasyl P | Prysyazhnyuk VP |
|---|---|---|---|---|---|---|---|
| 2014 | 2008 | 2012 | 2013 | 2011 | 2020 | 2017 | |
| Selection | |||||||
| Adequate definition of cases | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Representativeness of cases | 1 | 1 | 1 | 1 | 1 | 0 | 0 |
| Selection of control subjects | 1 | 0 | 0 | 0 | 0 | 1 | 0 |
| Definition of control subjects | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Comparability | |||||||
| Control for important factor or additional factor | 1 | 1 | 1 | 1 | 1 | 2 | 1 |
| Exposure | |||||||
| Exposure assessment | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Same method of ascertainment for all subjects | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Non-response rate | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| Total score | 8 | 7 | 7 | 7 | 7 | 8 | 6 |