risk and causality

Question 1

how can risk be measured?

Answer 1

• hazard ratios
• relative risk
• odds ratio
• attributable risk
• population attributable risk

Question 2

what is attributable risk?

Answer 2

the difference between the incidence in the exposed and that in the un-exposed.

Question 3

what is a population attributable risk?

Answer 3

the incidence of disease in a population attributable to the risk factor.

the absolute difference between risk in the total population and unexposed population

Question 4

what is the problem when it comes to calculating the population exposure risk?

Answer 4

getting the data about:

• incidence in the total population

(get from routine data)

• incidence among the exposed and non-exposed

(use data from cohort studies)

Question 5

define causation

Answer 5

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

Question 6

define association

Answer 6

an identifiable relationship between an exposure and disease

Question 7

what is a necessary cause?

Answer 7

an exposure which is necessary for disease to occur

a necessary cause must always precede the disease

Question 8

what is.a sufficient cause?

Answer 8

a set of conditions is a sufficient cause when it always produces the outcome

Question 9

what is a contributing cause?

Answer 9

a non-necessary factor that is needed in the one or more of cases