Table II.
Methodological quality of studies included in the final analysis based on the Newcastle-Ottawa Scalea for assessing the quality of cohort studies (n=23).
| Selection | Comparability | Outcome | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
|
|
|
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| First author/s, year (n=23) | Representativeness of the exposed cohort | Selection of the non-exposed cohort | Ascertainment of exposure | Outcome of interest was not present at start of study | Control for important factor or additional factor | Assessment of outcome | Follow-up long enough for outcomes to occur | Adequacy of follow-up of cohorts | Total | (Refs.) |
| Nguyen et al, 2009 | 0 | 0 | 1 | 1 | 2 | 1 | 1 | 1 | 7 | (27) |
| Poulsen et al, 2009 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (28) |
| Boursi et al, 2017 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 6 | (29) |
| Brusselaers et al, 2017 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | (30) |
| Hwang et al, 2017 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (31) |
| Wennerström et al, 2017 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | (32) |
| Cheung et al, 2018 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (33) |
| Hwang et al, 2018 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (34) |
| Li et al, 2018 | 0 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 8 | (35) |
| Tran et al, 2018 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (36) |
| Brusselaers et al, 2019 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | (37) |
| Kao et al, 2019 | 0 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 8 | (38) |
| Babic et al, 2020 | 0 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 8 | (39) |
| Brusselaers et al, 2020 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | (40) |
| Liu et al, 2020 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (41) |
| Kamal et al, 2021 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 | (42) |
| Lei et al, 2021 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (43) |
| Ng et al, 2021 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (44) |
| Seo et al, 2021 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (45) |
| Shin et al, 2021 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (46) |
| Abrahami et al, 2022 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (47) |
| Abrahami et al, 2022 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (48) |
| Gong et al, 2022 | 1 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 9 | (49) |
a
Each study can be awarded a maximum of one point for each item within the selection and exposure categories, while a maximum of two points can be given for the comparability category. Mean score, 8.4.