What is epidemiology?

Question 1

What is epidemiology?

Answer 1

The study of the distribution and determinants of health related states or events in specific populations

Question 2

How do communicable and chronic diseases vary in aetiology?

Answer 2

Communicable disease = cause is singular and deterministic e.g. if you get infected with cholera, you will get ill)

Chronic disease = cause is multifactorial and probabilistic e.g. even having a genetic predisposition, smoking, drinking alcohol and a unhealthy diet doesn’t mean you will get the disease but increases risk.

Question 3

What are the 9 Bradford hill points?

Answer 3

1) strength of association
2) consistently of association
3) specificity of association
4) temporality
5) dose-response
6) plausibility
7) coherence
8) experimental (or interventional) evidence
9) analogy

Question 4

Is a strong or weak association more likely to be causal?

Answer 4

Strong association

Question 5

Does a weak association disprove causality?

Answer 5

No

Question 6

What is consistency of association?

Answer 6

Seeing association between two variables regardless of who is studied and how

Question 7

What is coherence of evidence?

Answer 7

Does evidence findings match findings from other studies

Question 8

What is the prevention paradox?

Answer 8

A smaller risk affecting more people produces more cases than a high risk affecting less people so prevention targeted at high risk groups is less effective at reducing cases.

Question 9

What is attributable risk?

Answer 9

A measure of the proportion of morbidity or mortality that can be attributed to a given exposure

Question 10

What is background risk?

Answer 10

The base level of risk due to incidence of disease not due to a particular exposure (e.g. the risk of lung cancer in non-smokers based on the incidence of lung cancer in people who never smoked)

Question 11

What is the relationship between attributable risk and potential for prevention?

Answer 11

Attributable risk = potential for prevention

Question 12

What is factual exposure and counterfactual exposure?

Answer 12

Factual is what is the current situation/level of exposure/incidence/mortality? and the counterfactual is what would the situation be/level of exposure/incidence/mortality if we implemented an intervention/prevention?

E.g. factual = patients current risk of lung cancer vs counterfactual = patients risk if they stopped smoking