Homework answers / question archive / Study Proposal A: Cesarean Birth as a Risk Factor for the Development of Inflammatory Bowel Disease in Youth / Early Adulthood The purpose of this exercise is to demonstrate that you have sufficiently grasped the materials presented in this course

Study Proposal A: Cesarean Birth as a Risk Factor for the Development of Inflammatory Bowel Disease in Youth / Early Adulthood The purpose of this exercise is to demonstrate that you have sufficiently grasped the materials presented in this course

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Study Proposal A: Cesarean Birth as a Risk Factor for the Development of Inflammatory Bowel Disease in Youth / Early Adulthood

The purpose of this exercise is to demonstrate that you have sufficiently grasped the materials presented in this course. It will comprise 12% of your final grade. Please respond to each question below as briefly but completely as possible. Think like an epidemiologist! Please limit your paper to 5 pages or less.

 

Introduction:

 

Cesarean delivery comprises a significant proportion of births globally, with combined rates of planned and unscheduled cesarean delivery in a number of regions approaching 50%. The rate for cesarian delivery has increased in the United States over the past two decades such that it now reaches nearly 40%, with most of that increase attributable to planned (non-emergent) surgical delivery. Observational studies have shown that offspring born by cesarean delivery are at increased risk of ill health in childhood and adolescence, but these studies have often not adjusted for key confounding variables. A further challenge in this research has been that cesarian birth is justified to varying degrees, from life-threatening conditions (e.g. abruption, eclampsia) to patient or physician convenience. Various studies have shown outcomes as diverse as asthma, childhood obesity, inflammatory bowel disease (IBD), type 1 diabetes, cancer, and autism/autism spectrum disorder (ASD).

 

The following questions refer to a situation where you are an epidemiologic investigator proposing to study long-term IBD outcomes related to non-emergency cesarian birth, and requesting funds to do so from a federal agency, the National Institutes of Health.  

 

1. (2 pts total) What kinds of epidemiologic information would you provide to the federal agency to justify your request for money to study this question? [HINT: Do not review the specific information about conditions, but focus instead on what kind of information you would need]

- (1 pt) Where would you get this information?

- (1 pt) Describe sources specifically, and explain why you feel these would be the best sources.

 

2. (5 pts total) You review the existing literature, and decide to study if IBD occurs more frequently among those who were born by cesarian section. You are given the okay to go ahead by NIH.  Now, what kind of study would you plan to do? 

-  (1 pt) State clearly the basic study design.

-  (1 pt) Why did you choose this particular approach?

-  (1 pt) Outline your strategy for choosing participants.

-  (1 pt) How will you specify risk factors and outcomes?

-  (1 pt) State the null and alternative hypotheses for your study

 

3. (3 pts total)

  (1 pt) What are the major biases you'd expect to encounter in carrying out your study?

 (1 pt)  How would you set up your study to minimize the impact of these potential biases? 

(1 pt) What impact could these biases have on the validity and results of your study?

 

 

4. (2 pts) You complete your study and report that indeed, there appears to be an association of cesarian birth with greater risk for IBD. The association is statistically significant at the 95% level. What additional information might increase your belief that this is a true effect, in the causal pathway, rather than an artifact?

 

Correct responses to the Study Proposal questions should be based on the following:

 

Q1. (2 pts total) Lay out what kind of epidemiologic information will be needed for a plan to study your topic. Do not do a literature search and give me the information.

Your answers to Q1 should be based in large measure on information in Lectures 1 and 6 and the associated reading assignments: Gordis chapters 3-5, 18.

 

Q2. (4 pts. total) Your answer to this question depends on what basic study design you choose. Correct answers to Q2 are based on lectures 4, 5 or 6, and Gordis chapters 9 (cohort), 10 (case-control), 11-13.

 

Q3. (4 pts. total) Your answer to this question again depends on what basic study design you choose.

Correct answers to Q3 are based on lectures 3, 5 (cohort) or 6 (case-control), and Gordis chapters 9 (cohort), 10 (case-control), 11-13; 15.

 

Q4. (2 pts) Additional criteria to increase your belief that this is a true effect, in the causal pathway, rather than an artifact.

Correct answers to Q4 are based on lectures 1 and 3, and Gordis chapters 1,2,14,15.