Transcript Why should medical students be interested in EPIDEMIOLOGY?

Why should medical students
be interested in
EPIDEMIOLOGY?
Very basic concepts
What is EPIDEMIOLOGY?
Epidemiology is the study of the distribution
and determinants of health-related states or
events in specified populations, and the
application of this study to control of health
problems.
Last ed. Dictionary of Epidemiology
But can you imagine what is
epidemiology like in clinical practiceby
reading definition?
Let's see some examples
First, I will show you observational
data of mortality.
Mortality in Area A and Area B
Area A
Area B
dead/populatio
n
500/10,000
1000/10,000
mortality
5%
10%
If you categorize the populations by age
and compare mortality of Area A with that
of Area B
area A
age<60
area B
dead/popu 500/10,00
250/5,000
lation
0
mortality
dead/popu
60=<age
lation
mortality
5%
5%
0/0
750/5,000
-
15%
The factors should be taken into
consideration when you look at the data.
age
sex
race
year of birth
.
Answer
CDC revised classification system for HIV
(AIDS) infection in 1993
Next example
subjects:
smokers: 1000
non smokers: 1000
of same age range, sex ratio
status of lung cancer for 5 years were
observed.
Results in 5 years
smokers
non smokers
lung cancer/
1,000
50/1,000
10/1,000
morbidity
5%
1%
If the sample size of both
group is not 1,000, but 100.
smokers
not
smokers
lung cancer/ total
5/100
1/100
morbidity
5%
1%
Next example
lung cancer
healthy
alcohol intake
yes/ no
71/29
52/48
yes/no ratio
2.45
1.08
p=0.006 by Chi-square test
Non-smokers
lung cancer
healthy
alcohol intake
yes/ no
8/22
16/44
yes/no ratio
0.36
0.36
p=1.0 by Chi-square test
Smokers
lung cancer
healthy
alcohol intake
yes/ no
63/7
36/4
yes/no ratio
9
9
p=1.0 by Chi-square test
Why should medical students
be
interested in
EPIDEMIOLOGY?
Welcome to the world of
Epidemiology