Table 2.
Newcastle–Ottawa scale (NOS) scores for the studies included in the meta-analysis.
| Study | Selection | Comparability | Exposure | |||||
|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 1 | 1 | 2 | 3 | |
| Zhang 2007 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
| Arnold 2008 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
| Miao 2010 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
| Phusantisampan 2012 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
| Prato 2009 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
| Zhang 2015 | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Gunadi 2016 | ★ | ★ | ★ | ★ | ★ | |||
| Yang 2017 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
| Li 2017 | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Qian Jiang 2021 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
| Yang Wang 2020 | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Kristy Iskandar 2022 | ★ | ★ | ★ | ★ | ★★ | ★ | ★ | |
1. Adequate case definition; 2. Representativeness of the cases; 3. Selection of controls; 4. Definition of controls. Comparability: 1. Comparability of cases and controls on the basis of the design or analysis. Exposure: 1. Ascertainment of exposure; 2. The same method of ascertainment for cases and controls; 3: Non-response rate.