Table 4.

Risk of bias assessment using JBI’s critical appraisal tools for case-control studies

Items for critical appraisal	Were the groups comparable other than the presence of disease in cases or the absence of disease in controls?				Were cases and controls matched appropriately?				Were the same criteria used for identification of cases and controls?				Was exposure measured in a standard, valid and reliable way?				Was exposure measured in the same way for cases and controls?				Were confounding factors identified?				Were strategies to deal with confounding factors stated?				Were outcomes assessed in a standard, valid and reliable way for cases and controls?				Was the exposure period of interest long enough to be meaningful?				Was appropriate statistical analysis used?								Overall appraisal	Quality of the evidence
studies	yes	No	Unclear	Not applicable	yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable	Yes	No	Unclear	Not applicable
Morio et al. [27]	√				√					√			√				√					√			√				√				√				√				√				Included	High
Shetty et al. [54]	√				√				√											√	√				√					√			√				√				√				Included	High
Rommel et al. [55]			√		√				√				√						√		√				√				√				√				√				√				Included	High
Nives Protrka et al. [24]		√					√		√				√				√				√				√						√		√				√				√				included	moderate