Table 4 Newcastle‒Ottawa Scale risk of bias assessment scores for cohort studies
Study | Selection | Comparability | outcome | Overall quality | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Representativeness of exposed cohort | Selection of controls | Source of ascertainment | The outcome of interest was not present at the start of the study | Comparable on confounders | Outcome assessment | Adequate follow-up time (>5 years) | Adequacy of follow up | |||||||
Truly | Somewhat | Reliable record | Structured survey | study control for the most important factors | study control for the other important factors | Independent blind assessment | Record linkage | Complete follow-up | >95% follow-up or description provided of loss to follow-up | |||||
Tselepis, 1999 [22] | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 6 |
Risum, 2019 [25] | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 7 |
Turoňová, 2018 [26] | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 8 |
Studart, 2015 [27] | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 8 |
Mani, 2016 [29] | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 0 | 7 |
Sun, 2019 [31] | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 8 |
Shen, 2012 [32] | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 0 | 0 | 1 | 8 |