Case-control studies
-use 2x2 table with exposed/non-exposed on left and cases/controls on right
Case exposure rate
A/A+C
Control exposure rate
B/B+D
Odds of exposure in cases
A/C
Odds of exposure in controls
B/D
Odds ratio in case/control
- (A/C)/ (B/D)
OR and RR
-If a disease is very rare then OR= RR
OR values
values of 0- infinity
Cohort studies
Absolute risk of disease in exposed
A/A+B
Absolute risk of disease in non-exposed
C/C+D
Odds of finding the disease in the exposed
A/B
Odds of finding the disease in the non-exposed
C/D
Odds ratio in cohort
(A/B)/(C/D)
Risk difference
AR exposed-AR non-exposed
ARR
(A/A+B)-(C/C+D)
RR
(A/A+B)/(C/C+D)
Population attributable risk
ARRx proportion exposed