Study Designs: Cohort Studies Epidemiology find the actual question in the attachment below

Ch. 7 – Study Designs: Cohort
Calculate and interpret relative risk
Instructions:
Answer the following questions. If calculations are involved, be sure to show your work for full credit.
1. (5 points) Explain why using a cohort analysis vs. a series of cross-sectional studies to examine the age of
lung cancer onset in the U.S. population between 1900 and 2000 might yield different results.
Answer:
2. (4 points) What tool do epidemiologists use to estimate life expectancy?
Answer:
3. (4 points) Compare cohort study design to cross-sectional and case-control study design. Include at least
two strengths and two weaknesses of the cohort study design in your answer.
Answer:
4. (4 points) In what situation would it be beneficial to draw a study sample from an exposure-based cohort
instead of a population-based cohort?
Answer:
5. (20 points) Researchers study the possible association between teenage pregnancy and having a history of
child abuse among a cohort of 625 females ages 13-18.
Of 225 teenage females who had a history of child abuse, 175 were pregnant.
Of 400 teenage females who had no history of child abuse, 162 were pregnant. Using this information, fill in
the 2×2 table, calculate and interpret the relative risk.
Answer:
Fill in the 2×2 Table:
Teenage pregnancy
History of child abuse
yes No Totals
Yes
No
Totals
Relative Risk =
Interpretation:
6. (4 points) Match the study description to the correct study design. (Note: this question also covers
information presented in Chapters 6 and 7)
Choices: Prospective cohort
Retrospective cohort
Cross-sectional
Case-control study
a. A researcher hypothesizes that consumption of highly caffeinated energy drinks increases the risk for
death due to myocardial infarction (heart attack). The researcher decides to follow a group of 10,000 recent
graduates of the University of Missouri for 5 years, classifying them based on whether they regularly
consume energy drinks or not. At the end of the 5 years, researchers will determine which persons in the
study population passed away from a fatal heart attack.

b. Researchers want to determine if smoking increases the risk of stroke. They review the medical records of
all patients at a large hospital, classify the subjects based on history of smoking (yes or no) and then
comparing
c. Researchers want to determine if smoking increases the risk of stroke. They review the medical records of
all patients at a large hospital, select patients who had a stroke, randomly select patients who did not have a
stroke (matched on age and sex), and compared them on the basis of smoking history (yes or no).
d. Researchers assess the trend in diabetes prevalence over a 20 year period in the United States population
by conducting an annual survey of a sample representative of the population over the time period of interest.
7. (15 points) As an epidemiologis,t you are going to investigate the effect of a drug suspected of causing
malformations in newborn infants when the drug in question is taken by pregnant women during the course
of their pregnancies. As your sample you will use the next 200 single births occurring in a given hospital. For
each birth a medication history will be taken from the new mother and from her doctor; in addition, you will
review medical records to verify use of the drug. [Note: These mothers are considered to have been followed
prospectively during the entire course of their pregnancie, because a complete and accurate record of drug
use was maintained during pregnancy.] The resultant data are:
Forty mothers have taken the suspected drug during their pregnancies. Of these mothers, 35 have delivered
malformed infants. In addition, 10 infants of mothers who did not take the suspected drug are born with
malformations.
A. Complete the 2×2 table using the date provided:
Malformation in newborn
Drug exposure Yes No Totals
Yes
No
Totals
B. What is the relative risk between exposure to the drug and malformations in newborns?
C. Suppose that a relative risk of 0.5 has been found. How would you interpret that result?