Table A1.

Table summarising the results of the CASP case–control critical appraisal of all case–control study design papers.

Criterion	Latz et al. [23]	Iwawaki & Schuller [16]	LeBourgeois et al. [30]	Liu et al. [31]	Mindell et al. [17]	Mindell et al. [42]	Hense et al. [32]	Kohyama et al. [33]	Sadeh et al. [24]	Dewald et al. [25]	Mindell et al. [34]	Short et al. [35]	Varzsonyl et al. [26]	Chaput et al. [43]	Mindell et al. [44]	Mindell et al. [45]	Ahn et al. [36]	Biggs et al. [37]	Irwanto et al. [41]	Tynjälä et al. [27]	Mindell et al. [38]	Takahashi et al. [39]	Carneiro et al. [28]	Daban & Goh [40]	van Selms et al. [29]
Clearly focused question	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
Appropriate design	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
Clearly defined recruitment	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
Sample size based on a power calculation a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a	n/a
Outcome measurements valid and reliable	✕	✕	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✕	✓	✓	✓	✓	✓	✓	✕	✓	✓	✓	✓	✕
Exposure measurements valid and reliable	✕	✓	✓	n/a	p	p	p	p	p	n/a	p	✕	✕	p	p	✓	p	✕	n/a	✕	✓	✕	✕	✓	✕
Confounding factors accounted	✕	✕	✓	✓	✓	✓	✓	✕	✕	✕	✓	✓	✓	✓	✓	✓	✕	✓	✕	✕	✕	✓	✕	✕	✕
Appropriate statistical analysis	✓	✕	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✕	✓	✓	✓	✓	✓
Precise estimate of effect	✕	✓	✕	✓	✓	✓	✓	✓	✕	✓	✓	✓	✓	✓	✓	✓	✓	✓	✕	✕	✓	✓	✕	✓	✓
Reliable results with acknowledged possible bias	✓	✕	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✕	✓	✓	✓	✓	✓
Ability to generalize results	✕	✕	✕	✕	✕	✕	✓	✕	✕	✕	✕	✕	✕	✕	✕	✕	✕	✕	✕	✕	✕	✓	✕	✕	✕
Interpretation related to the existing evidence	✓	✕	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓
Overall Methodological Quality	L	L	M	M	M	M	H	M	L	L	M	M	L	M	M	M	M	M	M	L	M	M	L	M	L

Note: ✓—Yes; ✕—No; n/a—not applicable (^a it means the study did not mention a power calculation); p—partially; L—Low (≤8); M—Moderate (≤10); H—High (≤12).