Table 2.
The quality assessment of included studies.
| Study (cohort) | Representativeness of exposed cohort (1) | Selection of non-exposed cohort (1) | Ascertainment of exposure (1) | Outcome not present before study (1) | Comparability (2) | Assessment of outcome (1) | Follow-up long enough (1) | Adequacy of follow up*(1) | Quality score |
|---|---|---|---|---|---|---|---|---|---|
| Gofrit et al. (2019a) | ⋆ | ⋆ | ⋆ | ⋆ | ** | ⋆ | ⋆ | ⋆ | 9 |
| Klinger et al. (2021) | ⋆ | ⋆ | ⋆ | ⋆ | ** | ⋆ | ⋆ | ⋆ | 9 |
| Kim et al. (2021) | ⋆ | ⋆ | ⋆ | ⋆ | ** | ⋆ | ⋆ | ⋆ | 9 |
| Makrakis et al. (2022) | ⋆ | ⋆ | ⋆ | ⋆ | ** | ⋆ | ⋆ | ⋆ | 9 |
| Weinberg et al. (2023) | ⋆ | ⋆ | ⋆ | ⋆ | ** | ⋆ | ⋆ | ⋆ | 9 |
⋆Follow-up period (median, ≥3 years; or maximum, ≥5 years) was considered enough. The quality of studies were assessed using the Newcastle–Ottawa (NOS) scale. The NOS scale is a star rating system that allocates a maximum of nine stars across three categories: participant selection (four stars; the first four columns, Column 2–5), comparability (two stars; Column 6) and measurement of outcome in cohort (three stars; Column 7–9). At last, the score (Column 10) of each study was calculated based on the summary. In addition, a high score means a low bias risk.