In a small pilot study, women with cardiovascular disease (CVD) were contacted a
ID: 3436535 • Letter: I
Question
In a small pilot study, women with cardiovascular disease (CVD) were contacted and asked whether they had ever used estrogen. Each woman with CVD was matched by age, race, weight, and parity to a woman without disease. The results are shown below:
Pair Number
Women with CHD
Women without CHD
1
Estrogen user
Estrogen non-user
2
Estrogen non-user
Estrogen user
3
Estrogen user
Estrogen user
4
Estrogen user
Estrogen non-user
5
Estrogen user
Estrogen non-user
6
Estrogen user
Estrogen non-user
7
Estrogen non-user
Estrogen non-user
8
Estrogen user
Estrogen non-user
9
Estrogen non-user
Estrogen user
10
Estrogen user
Estrogen user
11
Estrogen user
Estrogen non-user
12
Estrogen non-user
Estrogen non-user
Unmatch the pairs. What is the estimated relative risk of cancer when analyzing this study as an unmatched study design?
a. 0.25
b. 1.43
c. 2.80
d. 4.00
e. 3.00
Pair Number
Women with CHD
Women without CHD
1
Estrogen user
Estrogen non-user
2
Estrogen non-user
Estrogen user
3
Estrogen user
Estrogen user
4
Estrogen user
Estrogen non-user
5
Estrogen user
Estrogen non-user
6
Estrogen user
Estrogen non-user
7
Estrogen non-user
Estrogen non-user
8
Estrogen user
Estrogen non-user
9
Estrogen non-user
Estrogen user
10
Estrogen user
Estrogen user
11
Estrogen user
Estrogen non-user
12
Estrogen non-user
Estrogen non-user
Explanation / Answer
Estimated relative risk = (8*8)/(4*4) = 4
Hence the correct option is d.
Woman with CHD Woman without CHD Estrogen User 8 4 Estrogen Non User 4 8