09 Cohort and case-control studies

Question 1

What is a cohort study?

Answer 1

• observational study
• group individuals with similar characteristics
• two measurement options: select sample and measure exposure or select sample, divide into exposed and unexposed and measure than

Question 2

How to measure exposure and outcome?

Answer 2

exposure: routine data (blood samples), questionaire

outcome: standardised assessment, must be same for both groups

measurement by observation

Question 3

What is a case-control study?

Answer 3

• identification of individuals with and without a disease -> comparison of exposure to investigate a relationship

Question 4

How to select for case or control?

Answer 4

Case: patients

control: shouldn‘t have/had disease -> if so put them to case, representative for general public or similar to case

Question 5

What is important when doing analysis of case-control studies?

Answer 5

Since it is retrospective, no incidence calculation is possible and thus no RR

Question 6

(Dis-)advantages of case-control studies

Answer 6

Advantages:
- time and cost saving
- rare diseases can be studied

Disadvantages:
- no incidence calculation
- more possible biases

Question 7

Analysis of cross-sectional studies

Answer 7

• other name Prevalence study
• 4 groups (the fields of the table)
• instead of RR you get a prevalence ratio
• very resource saving