Reference no: EM132636329

Question 1. A cohort study is conducted to assess the associa¬tion between clinical characteristics and the risk of stroke. The study involves n = 1250 participants who are free of stroke at the study start. Each participant is assessed at study start (baseline) and every year thereafter for 5 years. Table 3-8 displays data on hypertension status measured at baseline and hyper-tension status measured 2 years later.
a Compute the prevalence of hypertension at baseline.
b. Compute the prevalence of hypertension at 2 years.
c. Compute the cumulative incidence of hyperten¬sion over 2 years.

Question 2. A case-control study is conducted to assess the relationship between heavy alcohol use during the first trimester of pregnancy and miscarriage. Fifty women who suffered miscarriage arc enrolled, along with 50 who delivered full-term. Each participant's use of alcohol during pregnancy is ascertained. Heavy drinking is defined as four or more drinks on one occasion. The data are shown in Table 3-10.
a. Compute the odds of miscarriage in women with heavy alcohol use during pregnancy.
b. Compute the odds of miscarriage in women with no heavy alcohol use during pregnancy.
c. Compute the odds ratio for miscarriage as a function of heavy alcohol use.

Question 3. A randomized trial is conducted to evaluate the efficacy of a new cholesterol-lowering medication. The primary outcome is incident coronary artery disease. Participants are free of coronary artery disease at the start of the study and randomized to receive either the new medication or a placebo. Participants are followed for a maximum of 10 years for the development of coronary artery disease. The observed data are shown in Table 3-11.
a. Compute the relative risk of coronary artery dis-ease in patients receiving the new cholesterol medi¬cation as compared to those receiving a placebo.
b. Compute the odds ratio of coronary artery disease in patients receiving the new cholesterol medica¬tion as compared to those receiving a placebo.
c. Which measure is more appropriate in this design, the relative risk or odds ratio? Justify briefly.

Question 4. In the study described in Problem 4, some patients were not followed for a total of 10 years. Some suffered events (i.e., developed coronary artery disease during the course of follow-up), whereas others dropped out of the study. Table 3-12 displays the total number of person-years of follow-up in each group.
a. Compute the incidence rate of coronary artery disease in patients receiving the new cholesterol medication.
b. Compute the incidence rate of coronary artery disease in patients receiving a placebo.

Question 5. A total of 150 participants are selected for a study of risk factors for cardiovascular disease. At baseline (study start), 24 are classified as hypertensive. At 1 year, an additional 12 have developed hypertension and at 2 years another 8 have developed hypertension. What is the prevalence of hypertension at 2 years in the study?

Question 6. A national survey is conducted to assess the association between hypertension and stroke in per sons over 75 years of age with a family history of stroke. Development of stroke is monitored over a 5-year follow-up period. The data are summarized in Table 3-13 and the numbers are in millions.

a. Compute the cumulative incidence of stroke in persons over 75 years of age.
b. Compute the relative risk of stroke in hypertensive as compared to non-hypertensive persons.
c. Compute the odds ratio of stroke in hypertensive as compared to non-hypertensive persons.

Question 7. A prospective cohort study is run to estimate the incidence of stroke in persons 55 years of age and older. All participants are free of stroke at study start. Each participant is followed for a maximum of 5 years. The data are summarized in Table 3-14.
a. What is the annual incidence rate of stroke in men?
b. What is the annual incidence rate of stroke in women?
c. What is the annual incidence rate of stroke (men and women combined)?

Attachment:- Bio questions.rar