Epidemiology Question: An epidemiological investigation, which began on January
ID: 140918 • Letter: E
Question
Epidemiology Question:
An epidemiological investigation, which began on January 1, 1980, identified a population of 1,000 people. Among those 1,000, 3 were found to already have leukemia. During the ten years of the study in those considered as population at risk, 5 new cases of leukemia were diagnosed. Of the total of 8 cases with leukemia, 4 deaths occurred during the ten year study period. Two additional people, neither of whom had leukemia, were lost to follow-up at some point during the study period. The diagram below indicates the experience of only those 10 described study participants (see footnotes for the meaning of 3 symbols). None of the remaining 990 study participants became ill, died or were lost to follow-up during the 10-year study period and hence were not shown in this diagram.
ID#
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
status
1
------
*-----
------
------
------
------
------
------
------
------
alive
2
------
------
------
*-----
------
------
------
------
------
------
alive
3
*
------
------
------
------
------
------
------
-----
dead
4
------
------
------
------
?
lost
5
------
------
------
------
------
------
*-----
-----
dead
6
------
------
------
------
------
------
------
------
------
*-----
alive
7
------
*-----
------
------
-----
dead
8
*
------
------
------
------
------
------
------
------
------
------
alive
9
------
------
------
------
------
------
------
?
lost
10
*
------
------
-----
dead
Footnotes for 3 symbols:
* indicates diagnosis of leukemia (on the first day of the year).
indicates death (on the last day of the year).
? indicates loss to follow-up.
c). What was the incidence density of leukemia during the 10 year study period? (10 points)
d). What was the leukemia case fatality rate during the 10 year study period? (5 points)
ID#
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
status
1
------
*-----
------
------
------
------
------
------
------
------
alive
2
------
------
------
*-----
------
------
------
------
------
------
alive
3
*
------
------
------
------
------
------
------
-----
dead
4
------
------
------
------
?
lost
5
------
------
------
------
------
------
*-----
-----
dead
6
------
------
------
------
------
------
------
------
------
*-----
alive
7
------
*-----
------
------
-----
dead
8
*
------
------
------
------
------
------
------
------
------
------
alive
9
------
------
------
------
------
------
------
?
lost
10
*
------
------
-----
dead
Explanation / Answer
D. the leukemia case fatality rate during the 10 years of the study period was that out of 10 participants 4 died in 10 years so the ratio of dead: alive is 2:5 so fatality rate is 40% in 10 years.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.