Table 2.
Scores of the Newcastle-Ottawa Scale.
| No. | First authors | Selection | Comparability | Exposure | Total | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| ① | ② | ③ | ④ | ⑤ | ⑥ | ⑦ | ⑧ | |||
| 1 | Lou [17] | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 5 |
| 2 | Xu [18] | 1 | 1 | 0 | 1 | 0 | 2 | 1 | 0 | 6 |
| 3 | Wu [15] | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 5 |
| 4 | Choi [16] | 1 | 1 | 0 | 1 | 0 | 1 | 1 | 0 | 5 |
| 5 | Polyzos [19] | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 6 |
①: is the case definition adequate? ②: representativeness of the cases. ③: selection of controls. ④: definition of controls. ⑤: comparability of cases and controls on the basis of the design or analysis. ⑥: ascertainment of exposure. ⑦: the same method of ascertainment for cases and controls. ⑧: nonresponse rate.