Lec 12. Association, casual inference and causality

Question 1

What is the cause definition?

Answer 1

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

Question 2

What does association mean again?

Answer 2

Relationships between exposure/treatment and an outcome/disease.

Question 3

What are the 3 types of association (relationships)?

Answer 3

Artifactual associations, Non-causal associations, and causal associations.

Question 4

What are artifactual associations?

Answer 4

Flat out wrong. Can arise from Bias and/or confounding

Question 5

What are non-casual associations?

Answer 5

Most of what we talked about recently.

Question 6

In what two ways do non-casual associations occur?

Answer 6

1. Disease may cause exposure, rather than exposure causing disease. 2. Disease and exposure both are related with a confounder

Question 7

What is a mediator?

Answer 7

Necessary step to get the outcome

Question 8

Can Confounders be mediators?

Answer 8

No

Question 9

What are three types of casual relationships?

Answer 9

1. Sufficient cause. 2. Necessary cause. 3. Component cause (risk factor)

Question 10

Define sufficient cause.

Answer 10

Any precursor by itself will cause disease.

Question 11

What is an example of sufficient cause?

Answer 11

genetic defect in a person

Question 12

Define necessary cause.

Answer 12

just because its there doesn’t mean someone is going to get the disease, but it is necessary. By itself not guaranteed.

Question 13

What is an example of necessary cause?

Answer 13

Mycobacterium tuberculosis, necessary cause for TB to be diagnosed, yet can be present in ppl without clinical symptoms.

Question 14

Define Component cause (risk factor).

Answer 14

Component that increases likelihood of disease.

Question 15

What are two interactions in causal research?

Answer 15

Synergism and parallelism

Question 16

What is an example of component cause?

Answer 16

Smoking leads to lung cancer

Question 17

Define synergism.

Answer 17

2 variables that make the relationship and association more likely together than any one by themselves.

Question 18

Define parallelism.

Answer 18

Risk factors that are either or present, can change the association.

Question 19

What are Hill’s criteria guidelines?

Answer 19

Guidelines to see if the observed association is a verdict of causation.

Question 20

What are the 5 Hills Criteria?

Answer 20

Strength, Consistency, Temporality, Biological Gradient, and plausibility.

Question 21

Define strength.

Answer 21

Refers to the size of association (RR/OR/HR). The stronger/bigger the number the more likely to be causal.

Question 22

True or False? 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 22

True

Question 23

Define consistency

Answer 23

Reproducibility, repeated observations. How consistent have other studies shown this relationship.

Question 24

Consistency may do what to the truth?

Answer 24

Obscure it.

Question 25

What is an example when consistency obscured the truth?

Answer 25

MHT (menopausal hormone therapy). Stated the MHT protected from heart disease and other problems when in reality it actually increased the likelihood of problems.

Question 26

Define temporality

Answer 26

Reflects that the cause proceeds the effect/outcome in time.

Question 27

What are two definitions pertaining to temporality?

Answer 27

Proximate cause and distant cause

Question 28

What is proximate cause?

Answer 28

Short-term interval

Question 29

What is distant cause?

Answer 29

Long-term interval

Question 30

What is an example of temporality?

Answer 30

Pt gets side effects as soon as starting some new medication

Question 31

Define biological gradient

Answer 31

Gradient means more harmful, if something is causative then more of it can be harmful. If its beneficial it should help more with more of it.

Question 32

What is an example of biological gradient?

Answer 32

Light smokers versus heavy smokers. Heavy smokers are 15 times more likely to develop lung cancer

Question 33

Define plausibility

Answer 33

Is it even possible? Can it be explained?

Question 34

What is an issue with plausibility?

Answer 34

Can fail us because we dont know everything

Question 35

What is an example of plausibility?

Answer 35

Stomach ulcers. We used to believe that they couldnt be an infectious disease but now we know there is actually an organism that does this.