Table 1 Assessing the risk of bias of included studies using the Newcastle-Ottawa Scale (NOS)
Selection | Comparability | Outcome | Quality | ||||||
|---|---|---|---|---|---|---|---|---|---|
Study | Representative-ness of the exposed cohort | Selection of the non-exposed cohort | Ascertainment of exposure | Outcome was not present at start of study | Comparability of cohorts based on control for confounders | Assessment of outcome | Was follow-up long enough for outcomes to occur | Adequacy of follow-up of cohorts | |
Hada et al., 2006 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Chiang et al., 2007 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Mochizuki et al., 2007 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Kozel et at., 2009 | ★ | - | ★ | ★ | - | - | ★ | ★ | Poor |
Hirose et al., 2011 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Nasi et al., 2011 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Tian et al., 2012 | ★ | - | ★ | ★ | - | - | ★ | ★ | Poor |
Groiss et al., 2013 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Mesquita et al., 2013 | ★ | - | ★ | ★ | - | - | ★ | ★ | Poor |
Park et al., 2017 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Li et al., 2019 | ★ | - | ★ | ★ | - | - | ★ | ★ | Poor |
Kim et al., 2020 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |
Gorban et al., 2023 | ★ | ★ | ★ | ★ | ★★ | - | ★ | ★ | Good |