Table 2.
Quality assessment for the nine cohort studies according to Newcastle–Ottawa scale (NOS)
| Study | Year | S | C | E | Total score | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| S1 | S2 | S3 | S4 | C1 | C2 | E1 | E2 | E3 | |||
| Baek [22] | 2023 | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 9 |
| Wang [23] | 2023 | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 9 |
| Wang [24] | 2023 | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | – | 8 |
| Zhou [13] | 2021 | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 9 |
| Woo [26] | 2020 | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 9 |
| Yi [27] | 2019 | ★ | ★ | ★ | ★ | ★ | – | ★ | ★ | ★ | 8 |
| Rigby [1] | 2019 | ★ | ★ | ★ | ★ | ★ | – | ★ | ★ | ★ | 8 |
| Li [28] | 2017 | ★ | ★ | ★ | ★ | ★ | – | ★ | ★ | ★ | 8 |
| Matsui [30] | 2016 | ★ | ★ | ★ | ★ | ★ | – | ★ | ★ | ★ | 8 |
★: The scale uses a star symbol (★) to represent points, and each star represents one point
S selection, C comparability, E exposure. S1 representativeness of the exposed cohort, S2 selection of the nonexposed cohort, S3 ascertainment of exposure, S4 demonstration that outcome of interest was not present at start of study. C1 comparability of controls for the most important factor, C2 comparability of controls for a second important factor. E1 assessment of outcome, E2 was follow-up long enough for outcomes to occur, E3 adequacy of follow-up of cohorts