Table 5.
Risks of bias within studies.
| Selection | Comparability | Exposure | ||||||
|---|---|---|---|---|---|---|---|---|
| Study sources | Is the case definition adequate? | Representative of cases | Selection of controls | Definition of controls | Determination of exposure | Same method for determining cases and controls | Nonresponse rates | |
| Suto et al. (18) | ★ | ★ | ★ | ★ | ★ | |||
| Usami et al. (86) | ★ | ★ | ||||||
| Takei et al. (63) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Shimodera et al. (37) | ★ | ★ | ★ | ★ | ★ | |||
| Ma et al. (38) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Takizawa et al. (39) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Zhu et al. (54) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Matsubara et al. (42) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Pu et al. (81) | ★ | ★ | ★ | ★ | ||||
| Akashi et al. (43) | ★ | ★ | ★ | ★ | ★ | |||
| Downey et al. (51) | ★ | ★ | ★ | ★ | ||||
| Gao et al. (44) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Pu et al. (64) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Tsujii et al. (65) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Pu et al. (74) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Schecklmann et al. (45) | ★ | ★ | ★ | ★ | ★ | |||
| Tsujii et al. (67) | ★ | ★ | ★ | ★ | ★ | |||
| Liu et al. (68) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Wang et al. (69) | ★ | ★ | ★ | ★ | ★ | |||
| Tsujii et al. (70) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Satomura et al. (80) | ★ | ★ | ★ | ★ | ||||
| Nishida et al. (71) | ★ | ★ | ★ | ★ | ★ | |||
| Rosenbaum et al. (72) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Pu et al. (73) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Koseiki et al. (78) | ★ | ★ | ||||||
| Pu et al. (74) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Schiffer et al. (88) | ★ | ★ | ★ | |||||
| Eschweiler et al. (89) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Tomioka et al. (46) | ★ | ★ | ★ | ★ | ||||
| Pu et al. (25) | ★ | ★ | ★ | ★★ | ★ | ★ | ||
| Matsuo et al. (26) | ★ | ★ | ★★ | ★ | ★ | ★ | ||
| Onishi et al. (77) | ★ | ★ | ||||||
| Rosenbaum et al. (52) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Ohtani et al. (47) | ★ | ★ | ★★ | ★ | ★ | ★ | ||
| Herrmann et al. (27) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Yamagata et al. (82) | ★ | ★ | ||||||
| Kondo et al. (53) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Shoji et al. (28) | ★ | ★ | ★ | ★ | ★ | |||
| Kinoshita et al. (29) | ★ | ★ | ||||||
| Kito et al. (30) | ★ | ★ | ★ | ★ | ★ | |||
| Kawano et al. (76) | ★ | ★ | ★ | |||||
| Matsuo et al. (31) | ★ | ★ | ★ | |||||
| Zhu et al. (54) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Okada et al. (55) | ★ | ★ | ★ | ★ | ★ | |||
| Uemura et al. (56) | ★ | ★ | ||||||
| Matsubara et al. (32) | ★ | ★ | ★ | ★ | ★ | |||
| Masuda et al. (48) | ★ | ★ | ||||||
| Kinou et al. (57) | ★ | ★ | ★ | ★ | ★ | |||
| Yamagata et al. (58) | ★ | ★ | ★ | ★ | ★ | |||
| Koike et al. (33) | ★ | ★ | ||||||
| Feng et al. (49) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Aoki et al. (83) | ★ | ★ | ||||||
| Noda et al. (59) | ★ | ★ | ★ | ★ | ★ | |||
| Hirano et al. (50) | ★ | ★ | ★ | ★ | ★ | |||
| Azechi et al. (34) | ★ | ★ | ★ | ★ | ★ | |||
| Nishizawa et al. (60) | ★ | ★ | ★ | ★ | ★ | |||
| Takamiya et al. (84) | ★ | ★ | ||||||
| Matsuo et al. (35) | ★ | ★ | ★★ | ★ | ★ | |||
| Ohta et al. (36) | ★ | ★ | ★ | ★ | ★ | |||
| Akiyama et al. (61) | ★ | ★ | ★ | ★ | ★ | ★ | ||
| Ohi et al. (62) | ★ | ★ | ★ | ★ | ★ | |||
| Shinba et al. (85) | ★ | ★ | ||||||
| Akashi et al. (79) | ★ | |||||||
| Liske et al. (40) | ★ | ★ | ★ | ★ | ★ | |||