Table 2.
The quality assessment of included studies of meta-analysis
| Study | Selection (0–4) | Comparability (0–2) | Outcome (0–3) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| REC | SNEC | AE | DO | SC | AF | AO | FU | AFU | Total | |
| Katri | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |
| Peng | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 7 | ||
| Dallah | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | |
| Jeong | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Sang | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Ga | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
| Roh | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
REC: representativeness of exposed cohort; SNEC: selection of nonexposed cohort; AE: ascertainment of exposure; DO: outcome not present at the start of the study; SC: control for important factors; AF: additional factors; AO: assessment of outcome; FU: length of follow-up; AFU: adequacy of follow-up