Lecture 12: Evidence Evaluation Observational studies 1

Question 1

What is the goal of descriptive epidemiology?

Answer 1

To exam patterns (of disease, health behaviours)

Question 2

What is the goal of Analytic epidemiology?

Answer 2

To evaluate relationships between risk/protective factors and disease

Question 3

What is the big picture for Analytic Epidemiology?

Answer 3

Is there a relationship (association)?
Exposure -> outcome

Exposure can be: drug (ex. statin), intervention (ex. diet), policy (ex. drug plan coverage)

Outcome can be: clinical measure (ex. cholesterol), disease outcome (ex. occurrence of cancer), patient satisfaction

Question 4

What are the goals of experimental epidemiology?

Answer 4

To evaluate effect of treatment/intervention on disease

Question 5

What kind of study design do descriptive and analytic epidemiology come under?

Answer 5

Descriptive and Analytic

Question 6

What comes under experimental epidemiologic study designs?

Answer 6

Randomized controlled trial and non-randomized

Question 7

In observational studies where are individuals followed (observed)?

Answer 7

Real-world settings

Question 8

In observational studies is there any intervention/exposure assignment by researcher?

Answer 8

No

Question 9

An analytic observational study what does it describe?

Answer 9

Describe relationship between exposure and outcome

Question 10

Is disease the exposure or outcome in an analytic study?

Answer 10

Can be either or

Question 11

An analytic observational study can evaluate?

Answer 11

An intervention, though not assigned by researcher

Question 12

An analytic observational study start includes

Answer 12

Defined hypothesis

Question 13

An analytic observational study ends with

Answer 13

Confirming or rejecting hypothesis

Question 14

In analytic epidemiologic studies what is population? Is it larger than the sample

Answer 14

Who we want to learn about
Yes

Question 15

In analytic epidemiologic studies what is the sample?

Answer 15

Who we will study

Question 16

What is a cohort study? and what is the starting point?

Answer 16

Observational, analytic study
- Starting point is exposure

Question 17

What does cohort mean?

Answer 17

Ancient Roman military unit, band of warriors
* Persons banded together
* Group of persons with common defining characteristic

Question 18

Steps of a cohort study

Answer 18

1. Identify exposure status
2. Follow individuals over time to see who develops outcome

Question 19

Cohort study flow

Answer 19

Look on slides

Question 20

What criteria is included in exposure of a cohort study flow

Answer 20

What, how, when

Question 21

What criteria is included in outcomes of a cohort study flow

Answer 21

What, when

Question 22

What is the key to a cohort study?

Answer 22

Participants are followed up to that outcomes so researchers know when that outcome occurred

Question 23

Measures of association in cohort studies are?

Answer 23

• Relative risk/Risk ratio (RR)
• Odds ratio (RO)

Question 24

Interpretation of RR to see if there is a relationship?

Answer 24

RR>1 - Association: Exposed group have higher risk of outcome than unexposed group

RR = No association

RR<1 - Inverse association - Exposed group have lower risk of outcome than unexposed group

Question 25

Interpretation of RR to see what is the strength of relationship?

Answer 25

RR > 1 - % increase = (RR -1) x 100

RR < 1 - % decrease = (1 - RR) x 100

Question 26

What are the advantages to a cohort study?

Answer 26

• Can establish incidence
• Can examine rare exposures
• Can study multiple outcomes

Question 27

What are the disadvantages in a cohort study?

Answer 27

• Lengthy and expensive
• Not suitable for rare outcomes
• Vulnerable to non-response, migration, loss to follow-up