Table 1 Methodological quality evaluation of included studies
Inclusion study | Selection | comparabbility | Exposure | total | |||||
|---|---|---|---|---|---|---|---|---|---|
adequate case definition | case representativeness | control selection | control definition | ascertainment of exposure | same method | non-response rate | |||
Matsuguma, H. 2005 [3] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
Inoue, M. 2011 [2] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
Asakura, K. 2012 [11] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
Flechsig. P. 2015 [10] | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 7 |
Kashiwabara, K. 2016 [12] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
Moon, S.M. 2017 [7] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
Hu, C. 2018 [9] | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 7 |
Ahn, S. Y. 2019 [8] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |