Table 1

Checklist for the assessment of methodological quality of cross-sectional studies, case–control studies and prospective cohort studies

Study type
Study objective
  1 Positive, if the study had a clearly defined objectiveCS/CC/PC
Study population
  2 Positive, if the main features of the study population are described (sampling frame and distribution of the population according to age and sex)CS/CC/PC
  3 Positive, if cases and controls are drawn from the same population and a clear definition of cases and controls is given and if subjects with the disease/symptom in the past 3 months are excluded from the control groupCC
  4 Positive, if the participation rate is at least 80% or if the participation rate is 60–80% and the non-response is not selective (data shown)CS/CC/PC
  5 Positive, if the participation rate at main moment of follow-up is at least 80% or if the non-response is not selective (data shown)PC
Outcome measurements
  6 Positive, if data on history of the disease/symptom is collected and included in the statistical analysisCS/CC/PC
  7 Positive, if the outcome is measured in an identical manner among cases and controlsCC
  8 Positive, if the outcome assessments is blinded with respect to disease statusCS/CC
  9 Positive, if the outcome is assessed at a time before the occurrence of the disease/symptomCC
Assessment of the outcome
 10 Positive, if the time period on which the assessment of disease/symptom was based was at least 1 yearPC
 11 Method for assessing injury status: physical examination blinded to exposure status (+); self-reported: specific questions relating to symptoms/disease/use of manikin (+), single question (−)CS/CC/PC
 12 Positive, if incident cases were included (prospective enrolment)CC
Analysis and data presentation
 13 Positive, if the measures of association estimated were presented (OR/RR), including CI and numbers in the analysisCS/PC/CC
 14 Positive, if the analysis is controlled for confounding or effect modification: individual factorsCS/PC/CC
 15 Positive, if the analysis is controlled for confounding or effect modification: other factorsCS/PC/CC
 16 Positive, if the number of cases in the final multivariate model was at least 10 times the number of independent variables in the analysisCS/PC/CC
  • Cross-sectional studies (CSs), case-control studies (CCs) and prospective cohort studies (PCs)