| | Study | Selection | Comparability | Exposure | Total quality score |
| | Yamada, 2015 | 3 | 1 | 3 | 7 | | Kahlert, 2011 | 3 | 2 | 3 | 8 | | Cellura, 2015 | 3 | 0 | 3 | 6 | | Huang, 2015 | 3 | 2 | 3 | 8 | | Jiang, 2017 | 3 | 2 | 3 | 8 | | Mastumura, 2015 | 4 | 2 | 3 | 9 | | Cruz-Gil, 2018 | 3 | 1 | 3 | 7 | | Koga, 2010 | 3 | 1 | 3 | 7 | | Zhu, 2017 | 3 | 2 | 3 | 8 | | Zhang, 2018 | 3 | 3 | 3 | 9 | | Yin, 2019 | 3 | 3 | 2 | 8 | | Marcuello, 2019 | 3 | 3 | 3 | 9 | | Guo, 2014 | 3 | 2 | 2 | 7 | | Han, 2012 | 3 | 2 | 3 | 8 | | Hu, 2018 | 3 | 0 | 3 | 6 | | Hung, 2015 | 3 | 2 | 3 | 8 | | Yu, 2016 | 3 | 1 | 3 | 7 | | Zhang, 2015 | 3 | 2 | 3 | 8 | | Zhu, 2010 | 3 | 2 | 2 | 7 | | Jiang, 2018 | 3 | 2 | 2 | 7 | | Cai, 2016 | 3 | 2 | 3 | 8 | | Li, 2014 | 4 | 2 | 3 | 9 | | Ibarrola-Villava, 2015 | 3 | 2 | 3 | 8 | | Wang, 2016 | 4 | 2 | 3 | 9 | | Wang, 2017 | 4 | 2 | 3 | 9 | | Wu, 2014 | 3 | 2 | 3 | 8 | | Zhu, 2018 | 3 | 2 | 3 | 8 | | Liu, 2018 | 3 | 3 | 3 | 9 | | Li, 2018 | 3 | 2 | 2 | 7 | | Zhu, 2019 | 2 | 3 | 2 | 7 | | Peng, 2018 | 3 | 3 | 3 | 9 | | Xu, 2014 | 4 | 2 | 3 | 9 | | Bai, 2017 | 3 | 2 | 3 | 8 | | Tan, 2015 | 3 | 0 | 3 | 6 | | Qu, 2014 | 2 | 1 | 3 | 6 | | Zou, 2019 | 3 | 2 | 3 | 8 | | Hu, 2016 | 3 | 1 | 3 | 7 |
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