Relative Risk and

1

• Lesson 11
• Relative Risk and
• the Odds Ratio

2

• The risk of disease, given exposure, is

P(D E)
The risk of disease, given no exposure, is
P(D E)
The relative risk is
3
6
RR
4
Cohort Study
n
5
The odds of disease, given exposure
The odds of disease, given no exposure
6
Disease Odds Ratio
OR
Can calculate as shown only from a cohort study
7
Case-Control Study
n
8
From a case-control study, we can calculate
things like
P(E D) ,
P(E D) ,
P(E D ) ,
P(E D )
The odds of exposure, given disease
9
Exposure Odds Ratio
OR
Can calculate as shown from a case-control study
10
a
b
c
d
ac
bd
OR
11
OR is used to estimate RR!
OR can be calculated in any study design!
12
200
300
13
200
300
(150)
OR
14
200
300
(150)
(180)
OR
15
200
300
(150)
(180)
OR
(120)
16
200
300
(150)
(180)
OR
(50)
(120)
17
200
300
(150)
(180)
OR
4.5
(50)
(120)
18
150/270
RR
2.56
50/230
150/390
RR
3.15
50/410
19
Yes No
89
153
20
Yes No
89
153
21
Yes No
89
153