Causation and Confounding Flashcards
Define causality
The relationship between an event and the second event where the second event is understood as a consequence of the first.
(Cause/Effect)
Define a cause
An event, condition, characteristic or a combination of these factors which plays an important role in producing the disease
Describe sufficient cause
Set of minimal conditions and events that inevitably produce disease
Constellation of all causes that contributes to one having the disease
Complete causal mechanism
Describe component cause
One cause among the constellation that makes up sufficient cause
Factors that work together with necessary cause to produce disease
Describe necessary cause
A factor that must be present before a disease occurs
3-step process in determining causation
- Is there an association between exposure/characteristic and risk of disease?
- Validity: Is it a true association; exclude bias, chance, and confounding
- Is the association likely a causal one
Criteria for establishing a confounder
There is a relationship between exposure and confounder
There is a relationship between confounder and disease
the confounder cannot be in the causal pathway of the exposure and the disease (i.e. show that the confounder does not cause the disease)
Define a confounder
An added variable that confused the association between the exposure and outcome
It can lead to the wrong conclusion in examination of the E-D association(i.e. create the appearance of an association when none exists, or hide it when it does exist)
How does one address confounders?
In study design -randomization -matching -restriction In data analysis -measure confounders then adjust for them through stratification or multivariable regression
Bradford-Hill criteria for determining causality
Strength of association Consistency Temporality (essential) Biological gradient Biological plausibility Coherence Experiment Analogy Specificity
