Relative Risk

Question 1

Describe relative risk

Answer 1

The ratio of two risks (probability an individual will experience event/disease)

Can be measured as a rate (number of outcomes per person TIME) or a risk (outcomes) ratio

The relative risk gives the strength of associated - the higher the relative risk the higher the association.

Question 2

What studies can relative risk be found it?

Answer 2

Longitudinal/Cohort and RCTs

This is because the population is split into an exposed and non exposed group.

Question 3

Why can’t case control studies calculate relative risk?

Answer 3

No cases of incidence

They’re in an disease and non disease groups hence the odds ratio can be found

Question 4

Equation for relative risk

Answer 4

Relative risk = Risk in exposed group/Risk in unexposed group

Question 5

If relative was 0.75 (e.g. use example of statin and risk of stroke) describe it

Answer 5

Point estimate for risk ratio is 0.75

This means that risk of stroke in statin group is 0.75 times that in placebo group

Question 6

Equation for absolute excess risk

Answer 6

Absolute excess risk = risk in exposed person - risk in unexposed person