Table 2 Risk of bias within included studies assessed using the Newcastle-Ottawa Scale
First author, year [reference] | Selection (maximum score 4⋆) | Comparability of cohorts (maximum score 2⋆) | Outcome (maximum score 3⋆) | Total score, risk of bias | |||||
|---|---|---|---|---|---|---|---|---|---|
Representativeness of the exposed cohort | Selection of non-exposed cohort | Ascertainment of exposure | Demonstration that outcome of interest was not present at start of study | Assessment of outcome | Duration of follow-up | Adequacy of follow-up | |||
Gornik, 2010 [21] | ⋆ | ⋆ | ⋆ | ⋆ | ⋆ | ⋆ | ⋆ | – | 7, medium risk of bias |
Gornik, 2010 [22] | ⋆ | ⋆ | ⋆ | – | ⋆ | ⋆ | ⋆ | – | 6, medium risk of bias |
McAllister, 2014 [23] | – | ⋆ | ⋆ | ⋆ | – | ⋆ | ⋆ | ⋆ | 6, medium risk of bias |
Van Ackerbroeck, 2015 [24] | ⋆ | ⋆ | ⋆ | ⋆ | ⋆ | ⋆ | – | – | 6, medium risk of bias |