| Table 1. Quality assessment of the studies by the Newcastle-Ottawa scale | |||||||||
| Study | NOS Items Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Criteria | |||||||||
| Criteria | Selection | Comparability
1a |
Results | Total | |||||
| 1 | 2 | 3 | 4 | 1 | 2 | 3 | |||
| Zhong et al., 2012 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Scoccia et al., 2012 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Busnelli et al., 2013 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Tan et al., 2014 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Chai et al., 2014 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Unuane et al., 2016 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Neto et al., 2016 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 7 |
| Unuane et al., 2017 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Cai et al., 2017 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Nacak et al., 2018 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 7 |
| Pekman et al., 2019 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Ke et al., 2020 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Poppe et al., 2020 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| He et al., 2020 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Gungor & Gungor, 2021 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 7 |
| Zhuang et al., 2021 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 7 |
| Rao et al., 2021 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Huang et al., 2021a | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
| Huang et al., 2021b | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 7 |
| Huang et al., 2021c | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 7 |
Subtitle: Selection 1: Representative of the exposed cohort; Selection 2: Selection of the non-exposed cohort; Selection 3: Ascertainment of exposure; Selection 4: Outcome of interest not present at the start of the study; Comparability 1a and 1b: Comparability of cohorts based on the design or analysis; Results 1: Assessment of outcomes; Results 2: Follow-up of cohorts; Results 3: Adequacy of follow-up of cohorts.