Assignment No. 2 – Study Designs and Quantifying Diseases
Answer the following. Read the questions carefully. Write or type your answers clearly showing the details of your calculations (just providing answers is not enough to earn points) using a pen or pencil. Scan or take pictures of your assignment and upload it on Canvas.
1. (2 points) Identify the study design described below. Also, discuss some strengths and weaknesses associated with the type of study design that you identified for the described study.
Persons diagnosed with new-onset Lyme disease were asked how often they walk through woods, use insect repellant, wear short sleeves and pants, etc. Twice as many patients without Lyme disease from the same physician’s practice were asked the same questions, and the responses in the two groups were compared.
2. (6 points) Five hundred people are enrolled in a 10-year cohort study. At the start of the study, 50 have diagnosed CVD. Over the course of the study, 40 people who were free of CVD at baseline develop CVD.
a. What is the cumulative incidence of CVD over 10 years?
b. What is the prevalence of CVD at baseline?
c. What is the prevalence of CVD at 10 years?
3. (6 points) A national survey is conducted to assess the association between hypertension and stroke in persons 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 here and the numbers are in millions.
Did Not Develop Stroke
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.
4. (6 points) A small cohort study is conducted in 13 patients with an aggressive cellular disorder linked to cancer. The clinical courses of the patients are depicted graphically below:
a. Compute the prevalence of cancer at 12 months.
b. Compute the cumulative incidence of cancer at 12 months.
c. Compute the incidence rate (per 100 person-month) of cancer.
d. Compute the incidence rate (per 100 person-month) of death.
Optional Bonus Question (1 point):
1. Describe any challenges and/or difficulties that you had with completing this assignment. If you did not have any difficulty, describe what helped you most to be successful on this assignment. Did you seek help from any resources (such as learning center, coming to office hours, working with a classmate), or yourself helped others in the class on this assignment?