I have a couple of questions from my homework I need help with:

As a nurse practitioner, you are involved in designing a case control study to explore the relationship between heart attack and exposure to certain turf pesticides. What is the ONE essential prerequisite of the control group?

	A.	Controls should not have been exposed to turf pesticides.
	B.	Controls should be free from heart attacks or any other condition that is closely associated with heart attacks.
	C.	Controls should be from both hospital and community settings.
	D.	Controls should be matched to cases on the exposure.
	E.	Controls should be matched with cases on age and gender.
	F.	Controls should be free from heart attack but could have double angioplasty

An investigator wanted to determine the association of prenatal vitamin supplementation with birth defects. By reviewing birth records during a single year in a large U.S. county, the researcher located 190 infants born with neural tube defects (NTDs). A total of 600 other births were selected at random from birth records as the control group. All mothers were given a questionnaire to assess their diet and vitamin use during pregnancy. Among mothers who gave birth to an infant with an NTD, 85 reported no use of supplementary vitamins during pregnancy; mothers of a total of 135 control infants reported no use supplementary vitamins during pregnancy. Based on this information and assuming that the association is not due to bias nor confounding, one can calculate the appropriate measure of association and conclude that:

	A.	Mothers who did not take supplementary vitamins were 2.06 times as likely to have an infant born with NTDs than mothers who took supplementary vitamins.
	B.	Infants with NTD were 2.8 times as likely to be born to a mother who did not take supplementary vitamins compared with infants not born with NTD.
	C.	Mothers who did not take vitamin supplements were 0.36 times as likely to have an infant born with NTDs as women who took vitamin supplementation.
	D.	Infants with NTD were 0.36 times as likely to be born to a mother who did not take supplementary vitamins compared with infants not born with NTD.

In a retrospective cohort study examining the association of smoking with the risk of asthma in adults, it is essential that:

	A.	The study sample is representative of the general population
	B.	Follow-up is greater than 75% in both the exposed and not exposed groups
	C.	Participants who smoked at baseline are excluded from the study.
	D.	There are equal numbers of persons in the exposed and not exposed groups
	E.	At baseline, participants should be free of oral cancer.
	F.	At baseline , participants and their immediate family members should be free of asthma.
	G.	At baseline, participants should be free of asthma.

In a case-control study, controls were matched to cases on sex and age. In addition, the researchers collected data on a number of potential confounding variables includingrace/ethnicity, smoking status, education, and alcohol consumption. In this study, the researchers should be able to study the association of the disease with which of the following factors?

	A.	Sex and age
	B.	Sex, age, race/ethnicity, smoking status, education, and alcohol consumption
	C.	Sex, age, race/ethnicity
	D.	Race/ethnicity, smoking status, education, and alcohol consumption
	E.	Smoking status, education, and alcohol consumption