Table 4 Newcastle-Ottawa Scale (NOS) summary assessment of risk of bias for non-randomized studies included in the systematic review
Quality criteria | Selection (4) | Comparability (2) | Exposure (3) | Total (9) | |||||
|---|---|---|---|---|---|---|---|---|---|
Is case definition adequate? (1) | Representativeness of the cases (1) | Selection of controls (1) | Definition of controls (1) | Comparability on basis of design or analysis (2) | Ascertainment of exposure (1) | Same method of ascertainment for cases and controls (1) | Non-response rate (1) | ||
Gorman and Smith 1991 [9] | ● | ● | ○ | ● | ○ ○ | ● | ● | ○ | 5 |
Soldanova et al. 2012 [7] | ● | ● | ○ | ● | ● ● | ● | ● | ○ | 7 |
Deguchi et al. 2015 [8] | ● | ● | ○ | ● | ● ● | ● | ● | ○ | 7 |