HadPop - Lecture 9

Question 1

What are the types of observational studies?

Answer 1

• Case controlled

- Cohort studies

Question 2

What is prospective cohort studies?

Answer 2

Recruit disease free individuals and classify them according to their exposure status.

Then after a set amount of time, you follow them up and measure the effect it had on their disease etc.

Question 3

Are cohort studies good for rare cases?

Answer 3

YES

Question 4

In a cohort study, can you calculate RR

Answer 4

YES

Question 5

How do you calculate relative risk?

Answer 5

Risk in exposed / risk in unexposed

RR < 1 = More chance of developing disease in exposed.

Question 6

What are the benefit of cohort studies?

Answer 6

• Good for rare exposure
• Can look at many outcomes from a single exposure
• Has temporality - hence you can observe the time sequence also

Question 7

What are the disadvantages of cohort studies?

Answer 7

• Bad for rare diseases
• Prone to loss to follow up
• Time consuming

Question 8

What bias can arise from cohort studies?

Answer 8

Information bias

Selection bias

Misclassification bias

Question 9

What are retrospective cohort studies?

Answer 9

Recruit disease free individuals and separate them into groups based on their exposure status and observe the outcome. this is based on PAST DATA!