Table 2.
Quality evaluation of included studies.
| References | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | Scores | Overall of quality |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Kim et al. (2006) | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 7 | High |
| Fernández et al. (2010) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 8 | High |
| Song et al. (2011) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 8 | High |
| Mura et al. (2012) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 8 | High |
| Collard et al. (2013) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 7 | High |
| Kishaba et al. (2014) | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 0 | 6 | Moderate |
| Kakugawa et al. (2016) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 | High |
| Okuda et al. (2019) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 8 | High |
| Kishaba et al. (2020) | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 8 | High |
| Homma Sakae et al. (2022) | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 7 | High |
(1) The representativeness of the exposure group; (2) selection methods for non-exposure groups; (3) the method for determining exposure factors, (4) there are no indicators to be observed before the start of the study; (5) the study controlled for the main factors; (6) the study controlled for other confounding factors; (7) evaluation of outcome events; (8) is the follow-up time long enough; (9) integrity of follow-up.