Exam 2 : lecture Association, Causal Inference & Causality

Question 1

Cause

Answer 1

Precursor event, condition or characteristic required for the occurrence of the disease or outcome

Question 2

Associations

Answer 2

Relationships between an exposure/ treatment and an outcome/disease

Question 3

3 types of association (relationships)

Answer 3

Artifacts also (AKA false)
Non-causal associations (related but not caused)
Causal associations ( one thing cause the other)

Question 4

Artifactual association

Answer 4

Arise from bias or confounding

Question 5

Non-causal associations

Answer 5

Disease may CAUSE the exposure
Or
Disease and exposure are both associated with a third factor (confounding) ex: coffee drinking & CHD

Question 6

Causal associations

Answer 6

Exposure causes outcome

Question 7

Types of causal relationships

Answer 7

Sufficient cause
Necessary cause
Component cause

Question 8

Sufficient cause

Answer 8

Cause which precedes a disease, if present, disease with ALWAYS occur
Ex: genetic abnormalities
Can have risk factors (component causes)

Question 9

Necessary cause

Answer 9

Cause which precedes a disease and has the following relationships:
-cause must be present for disease to occur; cause may also be present without disease occurring
Ex: tuberculosis
NO GAURANTEE OF OUTCOME

Question 10

Component cause

Answer 10

Risk factors
-if present/active, increases the probability (or likelihood) of disease
Ex: High LDL—

Question 11

Some patients must be _______________ or ______________ to disease before component cause induce disease (multi factorial)

Answer 11

Primed

Susceptible

Question 12

Interactions in causal research

Answer 12

Synergism

Parallelism

Question 13

Synergism

Answer 13

Work together
2 or more components cause such that the combined measure of effect is greater than the sum of the individual effects
(Need BOTH factors)

Question 14

Parallelism

Answer 14

Either
2 or more components causes such that the measure of effect is greater if either is present
(One or the other will give you the disease)

Question 15

Hill’s guidelines

Answer 15

Derived following US surgeon Generals 1964 report on smoking
-no hard and fast rule of evidences could be generated by to judge likelihood of causation, but the more you have, the better the causation

Question 16

Hill’s criteria (guidelines)

Answer 16

Strength
Consistency
Temporality
Biological gradient
Plausibility

Question 17

The higher number of criteria met, when evaluating an association, the ore likely it may be causal. What inference process is this?

Answer 17

Hill’s criteria

Question 18

Hill’s criteria :
Refers to size of the measure of association (RR/OR/HR)
-the greater the association the more convincing it is that the association might actually be causal
EX: smokers have up to 20 times greater risk of developing lung cancer compared to non-smokers

Answer 18

Strength

Question 19

T or F
A strong association is neither necessary nor sufficient for causality and weakness of an association is neither necessary nor sufficient for absence of causality

Answer 19

True

Question 20

Hill’s criteria:
The repeated observations of an association in different populations under different circumstances in different studies
EX: cause-effect relationship between cigarette smoking & CHD greatly strengthened by the fact that a large number of observational studies have consistently demonstrated an INCREASED RISK

Answer 20

Consistency (reproducibility)

Question 21

Consistency may still obscure the truth, T or F

Answer 21

True

Women’s health study (menopausal hormone therapy)

Question 22

Hill’s criteria:
The cause precede the effect/outcome in time
-time-ordered also describable 
*proximate cause
*distal cause
EX: 1. take medicine—>projectile vomit
          Take Medicine for 10 years—

Answer 22

Temporality

Question 23

Hill’s criteria:
Presence of a gradient of risk (dose response) associated with eh degree of exposure
EX: light smoker are 5 times more likely to develop lung cancer than non-smokers
Heavy smokers are 15 times more likely to develop lung cancer

Answer 23

Biological gradient

Question 24

Hill’s criteria:
Presence of biological feasibility to the association, which can be understood and explained
EX: infection H. Pylori cause PUD

Answer 24

Plausibility

Question 25

What is the issue with hill’s criteria “plausibility”

Answer 25

Decision on criterion-based from existing/known beliefs, which may be flawed or imcomplete