Table 2.
Newcastle-Ottawa Scale (NOS) score of included articles
| No. | Author | Year | Selection | Comparability | Exposure | Total | Average | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Adequate definition | Representativeness | Selection of Controls | Definition of Controls | Ascertainment of exposure |
Same method | Non-Response rate | ||||||
| 1 | Aktas [25] | 2011 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | 5.85 |
| 2 | Fu [26] | 2019 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |
| 3 | Genc [27] | 2011 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 5 | |
| 4 | Ismail [24] | 2019 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |
| 5 | Kukla [28] | 2010 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 5 | |
| 6 | Montazerifar [29] | 2017 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |
| 7 | Polyzos [30] | 2016 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 7 | |
| 8 | Su [31] | 2021 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |
| 9 | Waluga [32] | 2019 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | 5 | |
| 10 | Xia [33] | 2011 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |
| 11 | Yan [34] | 2019 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |
| 12 | Yilmaz [35] | 2011 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |
| 13 | Yu [36] | 2012 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 | |