A case-control study was conducted to examine the relationship between prenatal/early childhood cigarette smoke exposure and depression among adolescents. To conduct this study, 700 adolescents with clinically diagnosed depression and 700 adolescents with no diagnosis of depression were enrolled. All participants were asked to provide information on parental smoking history, with specific questions on whether a parent smoked during the participants early childhood (including prenatal period). Based on participant responses to survey questions about parental smoking history, it appears that 400 cases and 200 controls were exposed to cigarette smoking during the prenatal/early childhood period.

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Given the above information and data, what is the correct measure of association for the relationship between childhood cigarette smoke exposure and depression among offspring?

	RR = 2.23
	OR = 3.33
	OR = 2.23
	RR = 1.77

Later on, the investigators were able to obtain data from the parents of the study participants and correctly identify whether a parent smoked during a pregnancy or during the early childhood period.

Once investigators did this, it appeared that 10% of cases had incorrectly claimed to have been exposed to cigarette smoking prenatally/during early childhood (in other words, among cases: 10% of the exposed group were actually unexposed) and 20% of controls incorrectly claimed to have been unexposed to cigarette smoking prenatally/during early childhood (in other words, among controls: 20% of the unexposed were actually exposed). Based on data collected from parents as part of the original cohort study, the investigators were able to correctly re-classify cases and controls as being exposed or unexposed.

What is the new measure of association based on these corrected data?

	OR = 1.41
	RR = 1.12
	RR = 1.41
	OR = 1.12