3.Is this study retrospective, cross-sectional, or prospective? Explain your answer. Prospective, Because the exposure, aspirin use, was collected before the study outcome, which is cardiovascular mortality, all causes and cancer in this study.
4.What is the major exposure of interest, how was it defined and classified in the main analyses?
5.The outcomes of interest are all-cause, cancer, and cardiovascular mortality. How did the authors collect data on these outcomes?
6.What was the primary measure of association used to describe the relationship between the exposure and outcomes? Why do you think the authors chose this measure?
7.
Apart from the primary measure of association that the authors presented in table 2 (see your
answer to question 6), they provided data that allows us to calculate other measures of
association. Use the data in Tables 1 and 2 to compute the crude cumulative incidence ratio
and cumulative incidence difference for the association of daily aspirin use (1/day) compared
with no aspirin use on the outcome of cancer mortality for both cohorts combined. Show
your work and provide interpretations for these quantities.
For daily aspirin use, CI1=
!"#$
%"&#&’!!(%$
= 0.0726 over the course of study
EPI201: Homework 2
Page 4 of 8
NAME:
Yiyang Yue
For no aspirin, CI2=
"%()
("%$!’(%!*)
== 0.0610 over the course of study
CIR= CI1/ CI2=1.19
Interpretation: over the course of study, there is 1.19-fold higher cumulative incidence mong
the people who take aspirin 1/day compared to those who do not take aspirin.
CID= CI1- CI2=0.012
Interpretation: over the course of the study, there is 1.2% higher cumulative incidence of cancer
mortality in people who take daily aspirin compared with those who do not.
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- Fall '18
- Epidemiology, daily aspirin, Yiyang Yue
