Table 3 Assessment of primarily selected studies according to the JBI Critical Appraisal Checklist for Case Control Studies

1. Were the groups comparable other than the presence of disease in cases or the absence of disease in controls?

2. Were cases and controls matched appropriately?

3. Were the same criteria used for the identification of cases and controls?

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•

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4. Was exposure measured in a standard, valid, and reliable way?

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5. Was exposure measured in the same way for cases and controls?

•

•

6. Were confounding factors identified?

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7. Were strategies to deal with confounding factors stated?

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8. Were outcomes assessed in a standard, valid, and reliable way for cases and controls?

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•

•

9. Was the exposure period of interest long enough to be meaningful?

10. Was appropriate statistical analysis used?

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•