Table 2 Risk of bias assessment using the Newcastle–Ottawa Scale for cohort studies included in a meta-analysis
Study | Selection | Comparability | Outcome | Total score | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Exposed cohort | Non-exposed cohort | Ascertainment of exposure | Outcome of interest | The most important factor | Additional factor | Assessment of outcome | Length of follow up | Adequacy of follow up | ||
Lee 2007 [9] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 9 |
Widhalm 2019 [10] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 9 |
Chen 2017 [24] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 9 |
Hoshino 2016 [25] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 8 | |
Bisaccia 2018 [26] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 8 | |
Stiasny 2008 [27] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 7 | ||
Tolga 2012 [28] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | 7 | ||