Table 2

Quality of the included studies assessed by the Newcastle-Ottawa Scale

StudySelectionComparabilityExposureScores
Adequate
definition of cases
Representativeness
of cases
Selection
of controls
Definition of
controls
Control for
important factor
Ascertainment
of exposure
Same method
to ascertain as for
cases and
controls
Non-response rate
Oderda16 ☆☆8
Park14 ☆☆7
Quintero45 ☆☆6
Bertz12 ☆☆7
van Rhijn29 ☆☆7
Burger46 ☆☆7
Queipo-Zaragoza47 ☆☆7
Lopez-Beltran48 ☆☆8
Santos28 ☆☆7
Blanchet49 ☆☆8
Lee50 ☆☆7