Table 3.

Critical appraisal results of case–control studies

Study	Q1	Q2	Q3	Q4	Q5	Q6	Q7	Q8	Q9	Q10	Total % of “yes” to critical appraisal questions
Ravindran and Kutty 33	U	N	Y	U	Y	Y	Y	Y	Y	Y	70 (7)
Peter et al. 5	Y	Y	Y	U	Y	Y	Y	Y	Y	Y	90 (9)
Total % of “yes” to each critical appraisal question	50 (1)	50 (1)	100 (2)	0 (0)	100 (2)	100 (2)	100 (2)	100 (2)	100 (2)	100 (2)

Abbreviations: N, no; U, unclear; Y, yes.

^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?

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

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

^6.Were confounding factors identified?

^7.Were strategies to deal with confounding factors stated?

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

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

^10.Was appropriate statistical analysis used?