Table 2 Study quality evaluation via the Newcastle-Ottawa Scale
Study | Representativeness of the exposed cohort | Selection of the non-exposed cohort | Ascertainment of exposure | Outcome not present at baseline | Control for age and sex | Control for other confounding factors | Assessment of outcome | Enough long follow-up duration | Adequacy of follow-up of cohort | Total |
|---|---|---|---|---|---|---|---|---|---|---|
Worthmann [14] | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 8 |
Groschel [15] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
Geng [16] | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 6 |
Lu [17] | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 6 |
Yin [20] | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
Breniere [18] | 1 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 7 |
Dong [19] | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 9 |
Jeong [22] | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 8 |
Cai [21] | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 6 |
Li [23] | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 6 |