Association, Causal Inference & Causality

Question 1

Define cause.

Answer 1

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

Question 2

What are the three types of associations?

Answer 2

1. Artifactual (aka False)
2. Non-causal
3. Causal

Question 3

What association can arise from bias and/or confounding?

Answer 3

Artifactual

Question 4

What two ways can non-causal associations occur?

Answer 4

1. Disease may cause the exposure

2. The disease and the exposure are both associated with a third factor (confounding)

Question 5

What is a causal association?

Answer 5

Exposure ——> Outcome

Question 6

What are the types of causal relationships?

Answer 6

1. Sufficient cause
2. Necessary cause
3. Component cause

Question 7

Define Sufficient Cause.

Answer 7

A set of minimal conditions/events that inevitably produce disease

Cause precedes the disease and will always cause disease; rare, apart from genetic abnormalities

Question 8

Define Necessary Cause.

Answer 8

A cause which precedes a disease; must be present for the disease to occur however the cause may also be present without the disease occurring

Question 9

Define Component Cause.

Answer 9

A factor/element that, if present/active, increases the probability (or likelihood) of a particular disease

Some pts must be “primed” or “susceptible” to disease before Component Causes induce disease

Question 10

What is Component Cause also known as?

Answer 10

Risk Factor, RF

Question 11

What are the interactions of causal relationships?

Answer 11

1. Synergism

2. Parallelism

Question 12

Define Synergism

Answer 12

• Factors work together
• Biological-interaction of 2+ component-causes such that the combined measure of effect is greater than the sum of the individual effects

Question 13

Define Parallelism

Answer 13

• Factors that work in parallel

- Biological-interaction of 2+ component-causes such that the measure of effect is greater if either is present

Question 14

What is Multiple Causation?

Answer 14

Multiple Component-causes working in concert to collectively become Sufficient-causes

Question 15

What is the Epi Causal Inference Process?

Answer 15

Hill’s Guidelines

Question 16

What are Hill’s Criteria?

Answer 16

1. Strength
2. Consistency
3. Temporality
4. Biologic Gradient
5. Plausibility

Question 17

Define Strength

Answer 17

Refers to the 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

Question 18

Define Consistency

Answer 18

The repeated observations of an association in different populations under different circumstances in different studies

Question 19

What is Consistency also known as?

Answer 19

Reproducibility

Question 20

Define Temporality

Answer 20

It reflects that the cause precede the effect/outcome in time

Time-order also describable: proximate cause (short-term) and distant cause (long-term)

Question 21

Define Biologic Gradient

Answer 21

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

Question 22

Define Plausibility

Answer 22

Presence of a biologic feasibility to the association, which can be understood and explained (biologically/physiologically/medically)