Lecture 20 9/26/24

Question 1

Why is it important to consider risk factors when preventing disease?

Answer 1

-removal of risk factors that are the sole cause of disease prevents the disease
-removal of risk factors that are a cause of disease reduces occurrence of the disease
-presence of a risk factor increases pre-test probability of diseases
-clinical findings of early disease increases the pre-test probability of disease more than risk factors

Question 2

What are the cause and effect relationships that must be considered in medical decision making?

Answer 2

-impact of disease etiology and risk factors on diagnosis and prediction
-positive and negative effects of available therapies
-effects of prevention on disease

Question 3

What can cause an association?

Answer 3

-chance
-bias: errors in study design, implementation, analysis
-effect-cause: outcome prompts individuals to participate in studied factor
-confounding: additional variable associated with both studied factor and disease actually causes disease
-causation

Question 4

What are Koch’s postulates?

Answer 4

-organism is present in every case
-organism can be isolated from case and grown in pure culture
-organism causes disease when inoculated into susceptible animal
-organism can be recovered from animal and identified

Question 5

What is temporality?

Answer 5

cause must precede an effect in time

Question 6

What is strength of association?

Answer 6

the stronger the relationship between the risk factor and the outcome, the less likely that relationship is due to chance/something else

Question 7

What is a biological gradient?

Answer 7

evaluates whether increased exposure results in more of the outcome

Question 8

What is consistency?

Answer 8

repeated observation of an association in different populations/studies under different circumstances

Question 9

What is specificity of association?

Answer 9

whether or not the specified exposure leads only to the studied outcome

Question 10

What is biological plausibility?

Answer 10

whether or not the association makes sense in light of existing theories

Question 11

What is coherence with existing knowledge?

Answer 11

whether or not the association is consistent with available evidence

Question 12

What is experimental evidence?

Answer 12

having a randomized controlled trial that provides evidence of the association

Question 13

What is analogy?

Answer 13

eliminating other similar factors when studying an effect/outcome relationship

Question 14

What is publication bias?

Answer 14

greater likelihood that studies with positive results will be published

Question 15

What are the 13 things that need to be identified in a study for it to be credible?

Answer 15

-clearly stated objectives
-internal and external validity
-inclusions and exclusions
-group definition/allocation
-appropriately defined and applied procedures
-equal scrutiny of all groups/blinding
-appropriately defined outcome measures
-elimination of bias/confounding
-appropriate tools for statistical analysis
-correct interpretation of statistical analysis
-sample size determinations
-clear and complete results
-appropriate and complete conclusions