Causal Relationships

Question 1

An event, condition, or characteristic w/o which the dz. would not have occurred.

Answer 1

Cause

Question 2

What 3 factors do descriptive epidemiology aim to address?

Answer 2

• Agent factors
• Environmental influences
• Host factors

(all interact)

Question 3

List 3 Agent Factors

Answer 3

• Infection Rate
• Pathogenicity
• Virulence

Question 4

What are the 8 criteria for identifying cause-effect relationships?

Answer 4

• Strenght of association
• Temporal relationship
• Dose-response relationship
• Biological plausibility
• Consistency
• Elimination
• Reversible associations
• strength of study design

Question 5

List 3 types of Associations

(association doesn’t = cause)

Answer 5

• Non-statistical (chance)
• Statistical
• Risk Factors

Question 6

Casual factors can be:

(4)

Answer 6

• necessary & sufficient
• necessary but not sufficient
• sufficient but not necessary
• neither sufficient nor necessary (but contributes)

Question 7

Reversible associations?

Answer 7

Removal of a factor results in a decr. or incr. frequency of dz.

Question 8

List the epidemiologic study types in order of strongest to weakest for providing evidence that an association may be causal.

(5)

Answer 8

1. Radonmized clinical trials
2. Cohort & case-control
3. Cross-sectional
4. Case series
5. Case report

Question 9

List the 2 measures of strength of association & the tests the are used in

Answer 9

• Relative Risk (RR): cohort
• Odds Ratio (OR): case-control

Question 10

List 3 factors that impair making causal inferences.

Answer 10

• lengthy time interval btwn “cause” & dz.
• mulitple “causes” leading to same dz.
• causal factor requires other factors for dz. occurrence

Question 11

What are 3 characteristics of a Cause?

Answer 11

1. must precede the event
2. can be (+) or (-) in the presence of exposure
   
   1. vaccines
3. one or multiple casual factors

Question 12

Causal factors are

Answer 12

• Disease agents
• Environmental influences
• Host factors

(interactive)

Question 13

Characteristics of Confidence Interval

Answer 13

• includes P value
• same pop. sampled, resulting intervals would bracket the TRUE estimate of the pop. ~95 or 99% of the time
• depends on sample size (larger is better)

Question 14

What does (+) statistical association possibly indicate?

Answer 14

Causality

Question 15

What does (-) statistical association possibly indicate?

Answer 15

a protective factor