risk and causation

Question 1

measures of risk

Answer 1

strength of association
- relative risk
- hazard ratio
- odd ratio

impact of exposure in the population
- attributable risk
- population attributable risk

Question 2

attributable risk

Answer 2

the difference between the incidence in the exposed and that in the unexposed

Question 3

how to calculate AR

Answer 3

incidence in exposed - incidence in unexposed
Ie- Iu

Question 4

AR%

Answer 4

the proportion of disease among the exposed which
- can be attributed to the exposure
- could be avoided by eliminating the exposure

Ie- Iu/ Ie x100

Question 5

PAR (population attributable risk)

Answer 5

incidence of disease in a population attributable to the risk factor
= It- Iu
It= absolute difference between risk in the total population

Question 6

PAR %

Answer 6

proportion of cases in the population attributable to the exposure
expressed as a percentage of total risk in population
= It-Iu/ It x100

Question 7

causation

Answer 7

implies that there is a true mechanism that leads from exposure to disease

Question 8

association

Answer 8

an identifiable relationship between an exposure and disease
- implies that exposure might cause disease
- risk factors or risk markers or risk indicators

Question 9

why might an association not mean it is causal

Answer 9

bias
chance
confounding

Question 10

sufficient cause

Answer 10

complete causal mechanism that always produces disease and consists of many ‘component causes’

Question 11

analytical study types

Answer 11

observation:
- cross sectional
- case-control
- cohort studies

experimental
- randomised controlled trials