Table 2 Risk of bias assessment of the included studies
Study | Representativeness of the exposed cohort | Selection of the non-exposed cohort | Ascertainment of exposure | Outcome of interest was not present at start of study | Comparability of cohorts | Assessment of outcome | Adequacy of follow-up cohort |
|---|---|---|---|---|---|---|---|
Espie et al. 2007 [16] | Somehow representative | Drawn from the same community | No description | Yes | Study control for most important factors | No description | Yes |
Fournier et al. 2008 [8] | Somehow representative | Drawn from the same community | Written self-report questionnaires | Yes | Study control for most important factors | Self-report questionnaires or files of health insurance plan. (Pathology reports were obtained in 96 % of cases) | Yes |