Similar population | Assessment of exposure | Outcome not present at start of study | Adjustment of prognostic variables | Assessment of prognostic variables | Assessment of outcome | Adequate follow-up | |
von Knorring et al36 | ++ | + | − | −− | −− | − | + |
Chuang et al38 | + | ++ | −− | −− | ++ | −− | + |
Godeau et al37 | − | − | −− | −− | −− | −− | −− |
Behn et al39 | ++ | ++ | −− | −− | −− | −− | + |
Gouet et al40 | + | + | −− | −− | −− | −− | + |
Andersson et al41 | ++ | ++ | −− | −− | −− | −− | + |
Delecoeuillerie et al42 | ++ | ++ | −− | −− | −− | −− | + |
Nesher et al43 | ++ | ++ | −− | − | + | −− | + |
Gabriel et al44 | ++ | ++ | + | + | ++ | ++ | + |
Proven et al45 | ++ | ++ | + | + | ++ | ++ | + |
Hutchings et al46 | ++ | ++ | −− | + | + | + | −− |
Schmidt et al49 | ++ | ++ | − | + | + | −− | − |
Dasgupta et al50 | + | − | − | −− | −− | −− | + |
Khalifa et al51 | + | + | −− | −− | −− | −− | −− |
Martinez-Lado et al52 | + | ++ | −− | + | ++ | −− | + |
Mazzantini et al53 | ++ | ++ | ++ | + | + | ++ | + |
Dunstan et al54 | ++ | ++ | + | ++ | + | −− | + |
Alba et al55 | ++ | ++ | + | ++ | −− | + | + |
Carbonella et al58 | + | −− | −− | −− | −− | −− | − |
Farschou et al31 | ++ | ++ | + | − | ++ | ++ | ++ |
Muller et al57 | ++ | + | −− | −− | + | −− | − |
Question 1: was selection of exposed and non-exposed cohorts drawn from the same population? Question 2: can we be confident in the assessment of exposure? Question 3: can we be confident that the outcome of interest was not present at start of study? Question 4: did the study match exposed and unexposed for all variables that are associated with outcome of interest or did the statistical analysis adjust for these prognostic variables? Question 5: can we be confident in the assessment of the presence or absence of prognostic factors? Question 6: can we be confident in the assessment of outcome? Question 7: was the follow up of cohorts adequate?
++, definitely yes (low risk of bias); +, probably yes; −, probably no; −−, definitely no (high risk of bias).