Table 2 Quality assessment based on the NOS for observational studies
Author | Selection (out of 4) | Comparability (out of 2) | Outcomes (out of 3) | Total (out of 9) | |||||
|---|---|---|---|---|---|---|---|---|---|
Representativeness of exposed cohort | Selection of non-exposed cohort | Ascertainment of exposure | Outcome not present at the start of the study | Assessment of outcomes | Length of follow-up | Adequacy of follow-up | |||
Song | * | * | * | * | ** | * | 7 | ||
Ikeda | * | * | * | * | ** | * | 7 | ||
Kinoshita | * | * | * | * | ** | * | * | 8 | |
Kim MG | * | * | * | * | * | * | 6 | ||
Lee | * | * | * | * | ** | * | 7 | ||
Kim DG | * | * | * | * | * | * | * | 7 | |
Kim HG | * | * | * | * | * | * | 6 | ||
Choi | * | * | * | * | ** | * | 7 | ||
Chen | * | * | * | * | ** | * | * | * | 9 |
Zhang | * | * | * | * | ** | * | 7 | ||
Han | * | * | * | * | * | * | 6 | ||
Kanaji | * | * | * | * | ** | * | 7 | ||