epi RR

Question 1

Preventable fraction equations?

Answer 1

Incidence in unexposed-exposed/ incidence in unexposed.
Or 1-Relative Risk. ( Risk in exposed/unexposed)

E.g. Risk exposed = 3/10, Unexposed= 7/10.
7-3/7 = 0.57% preventable fraction.
RR= 3/7=0.43.
1-0.43=0.57

Question 2

PAF equations?

Answer 2

Incidence in population-incidence in unexposed/ incidence in population
This gives the fraction of incidence in the population that is due to the exposure.
Or
Px( RR-1)/ (Px(RR-1))+1 = PAF.
Where P is the prevalence, use if incidence rate unknown.

Question 3

PAF when incidence rate unknown?

Answer 3

Px( RR-1)/ (Px(RR-1))+1 = PAF.

Where P is the prevalence, use if incidence rate unknown.

Question 4

ARF when incidene rate unknown?

Answer 4

Relative risk-1/relative risk

Question 5

other word used to describe 5% (0.05)…

Answer 5

precision

Question 6

what sub-study can be done in a case control study to reduce confounding?

Answer 6

nested case control- pick out individual cases and controls with similar features and compare.

Question 7

1-Relative Risk=?

Answer 7

preventable fraction, but also the efficacy of a study