Table 3 NOS criteria for cohort study
Study | Representativeness of the exposed cohort | Selection of the non-exposed cohort | Ascertainment of exposure | Demonstration that the outcome of interest was not present at the start of the study | Comparability of cohorts on the basis of the design or analysis | Assessment of outcome | Was follow-up long enough for outcomes to occur | Adequacy of follow-up of cohorts | Total quality scores |
|---|---|---|---|---|---|---|---|---|---|
Schalk [15] | ☆ | ☆ | \ | ☆ | ☆ | ☆ | ☆ | \ | 6 |
Dosset al. [8] | ☆ | ☆ | ☆ | ☆ | ☆ | ☆ | ☆ | \ | 7 |