Association, Causal Inference & Causality Flashcards
Define Cause
a precursor event, condition, or characteristic required for the occurrence disease/outcome
most causal relationships involve multiple-component factors
Epidemiological studies yield __________ between exposure and disease
(statistical) associations
What are the 3 main types of association delineated during a study?
Artifactual (aka False) Associations
Non-Causal Associations
Causal Associations
Define Artifactual Associations
they can arise from bias and/or confounding
Define Non-Causal Associations
Occurs in one of two ways
The disease may cause the exposure (rather than the other way around)
The disease and exposure are both associated with a 3rd factor (confounding)
Define Causal Associations
There is a direct link between the exposure and the outcom
What are the 3 types of Causal relationships?
Sufficient Cause
Necessary Cause
Component Cause
Define Sufficient Cause. what is an example of this?
a set of minimal conditions that WILL cause disease
the cause always precedes the disease in this case
ex. genetic conditions
Define Necessary Cause. What is an example of this?
A cause that precedes the disease and MUST be present for the disease to occur
the cause may be present and the disease not occur in this case
ex. Mycobacterium tuberculosis
Define Component Cause. What is an example of this?
(aka risk factor) a factor that if present/active it increases the likelihood of a particular disease
ex. High HDL levels increasing he risk of AMI
Define synergism. Give an example of this
when 2 or more component causes interact and their combined measure of effect is greater than the sum of the individual effects
ex. genetic predispositions to depression and a stressful life event causing a synergistic effect on the risk of depression
Define Parallelism. Give an example of this
When 2 or more component causes interact in such a way that the measure of effect is greater if EITHER component is present
Multiple component causes can work together to collectively become ____________.
Sufficient Causes
What is used in the process of causal inference determination? give an example of this
Inductively-Oriented Criteria ; Hill’s Criteria (guidelines)
Explain Hill’s criteria in layman’s terms
the criteria that must be met to determine an observed association to be a verdict of causation
List the categories of Hill’s Criteria (guidelines)
- Strength
- Consistency
- Temporality
- Biologic Gradient
- Plausibility
Mnemonic: “Still Can’t Take Blue Pills”
Define Strength as it pertains to Hill’s Criteria
refers to the SIZE of the measure of association (RR/OR/HR)
the greater (below or above) 1, the more convincing the association may be causal
Define Consistency as it pertains to Hill’s Criteria
the repeated observations of an association in different populations.
the length of time an association is found to be consistent also matters
Define Temporality as it pertains to Hill’s Criteria
reflects that the cause precedes the effect/outcome in time
smoking causes lung cancer if you smoke prior to being diagnosed.
Define Biologic Gradient as it pertains to Hill’s Criteria
refers to the presence of a gradient of risk associated with a degree of exposure
can be a good or bad risk (smoking or exercise)
Define Plausibility as it pertains to Hill’s Criteria
refers to the biological feasibility to the association
has to be a logical cause
A strong association is neither necessary nor _____ for causality.
sufficient
the weakness of an association is neither necessary or sufficient for ABSENCE of causality
Compare proximate cause and distant cause when referring to temporality
Proximate cause: short-term interval
Distant Cause: long-term interval
True or false: consistency will alway be a sign of causality in a study
False
consistency may still obscure truth (ex. postmenoposal estrogen study)
