Table 2.
Quality assessment of included studies using Newcastle Ottawa Scale
| References | Selection |
Comparability |
Outcome |
Quality | |||||
|---|---|---|---|---|---|---|---|---|---|
| Representativeness of exposed cohort | Selection of nonexposed cohort | Ascertainment of exposure | Outcome not present at start | Adjustment for primary and secondary factors | Assessment by record linkage | Long enough follow up for outcome to occur | Adequacy of follow-up | ||
| Hezode et al. [16] | X | X | X | − | XX | X | X | X | High quality |
| Hezode et al. [17] | X | X | X | − | XX | X | X | X | High quality |
| Ishida et al. [29] | X | X | X | − | XX | X | X | X | High quality |
| Brunett et al. [28] | X | X | X | X | XX | X | X | X | High quality |
| Liu et al. [32] | X | X | X | − | XX | X | X | X | High quality |
| Kelly et al. [31] | X | X | X | X | XX | X | X | X | High quality |
| Adejumo et al. [27] | X | X | X | − | XX | − | X | − | Moderate quality |
| Kim et al. [30] | X | X | X | − | XX | − | X | − | Moderate quality |
| Nordmann et al. [33] | X | X | X | − | XX | X | X | X | High quality |
X, a point given in scale; XX, no point given in scale.