Epidemiological Study Designs

Question 1

What is a cohort study?

Answer 1

Exposed/unexposed studied.

Can be concurrent, retrospective.

Investigate CAUSE of disease

Question 2

Define case-control study

Answer 2

Pathology/no-pathology

looked back upon to see if exposed or unexposed.

ALWAYS RETEROSPECTIVE.

Investigates RISK FACTORS

Question 3

Outline what a cross-sectional study involves

Answer 3

Data collected from pop/representative subset, at specific point in time.

Provide data on entire pop under study.

Assess prevalence, causes of disease or results of intervention

Question 4

What is the difference between prevalence and incidence?

Answer 4

Prevalence (no. overall cases) vs incidence (no. new cases)

Question 5

How do you calculate prevalence?

Answer 5

Prevalence (no. overall cases) = incidence (no. new cases) x duration of disease

Question 6

What is risk ratio?

Answer 6

prevalence proportions at a particular time

= incidence of exposed / incidence of unexposed

Question 7

Describe rate ratio

Answer 7

compares incidence after a particular time period

= (Incidence exposed/disease free years) / (incidence unexposed/disease free years)

Question 8

What is odds ratio?

Answer 8

ratio of odds at a particular time

= odds of disease exposed / odds of disease unexposed