Lecture 14: Associations, Causal Interference, Causality

Question 1

Artifactual/False Association

Answer 1

False association which can arise from significant confounding or bias

Question 2

Non-Causal Association

Answer 2

There is an association, but it is not causal; disease may cause exposure or a 3rd variable is involved

Question 3

Causal Association

Answer 3

Causal association is present between exposure and outcome; sufficient, necessary, or component causes

Question 4

Sufficient cause

Answer 4

set of minimal conditions inevitably produces disease

ex: genetic disorders, such as Tay-Sachs

Question 5

Necessary cause

Answer 5

a cause which precedes the disease and must be present for the disease to occur, however, may be present without the disease occurring

ex: mycobacterium tuberculosis - is present in people who have TB, but is also present in some individuals without the disease

Question 6

Component cause

Answer 6

a characteristic that, if present and active, increases the probability of a particular disease

ex: High LDL levels = risk factor for MI, but not all persons with high LDL have MIs, and some MIs occur in those with low levels of LDL

Question 7

Hills Criteria: Strength

Answer 7

size of association - the greater an association, more convincing that it may be causal

Question 8

Hills Criteria: Consistency

Answer 8

AKA “Reproducability” - repeated observation of association in different populations under different circumstances in MANY different studies

Question 9

Hills Criteria: Temporality

Answer 9

the necessity that the cause PRECEDE the effect in time

Question 10

Hills Criteria: Biologic gradient

Answer 10

observation of a gradient of risk (dose-response) associated with degree of exposure

Question 11

Hills Criteria: Plausability

Answer 11

biological feasibility; association can be understood/explained