Description
Answer each questions below:
Chapter 3 Homework Assignment
1. Describe the two major types or approaches for measures of association that are
described in Chapter 3. Include in your description what specific measures or calculations
for each approach and the general formula that has been provided for you in both the text
and the lecture slides.
2. Suppose that an investigation of the association between regular physical activity and
ovarian cancer revealed that the incidence rate of ovarian cancer among women who
engaged in regular physical activity was 30 per 100,000 women-years of follow-up,
whereas the rate among women who did not engage in regular activity was 45 per
100,000 woman-years of follow-up.
a. Use this data to compute the incidence rate ratio of ovarian cancer for women
who are physically active versus women who are not.
b. State in words your interpretation of this measure
c. Compute the incidence rate difference of ovarian cancer for women who are
physically active versus women who are not.
d. State in words your interpretation of this measure
e. If there were no association between regular physical activity and ovarian
cancer, what would be the numeric values of the incidence rate ratio and
incidence rate difference?
3. The 58th annual convention of the American Legion was held in Philadelphia from July
21 until July 24, 1976. People at the convention included American Legion delegate, their
families, and other Legionnaires who were not official delegates. Between July 29 and
August 30, some of theose who had been present became ill with a type of pneumonia
that was subsequently named Legionnaires? disease. No one attending the convention
developed the disease after August 30. The numbers of delegates and nondelegates who
developed Legionnaires? disease during the period July 20 to August 30 (a 41 day period)
are summarized in the following table.
Developed Legionnaires? Disease
Convention Status
Yes
No
TOTAL
Delegate
125
1724
1849
3
759
762
Nondelegate
a. Compute the cumulative incidence of Legionnaires? disease among the
delegates and nondelegates.
b. Compute the cumulative incidence ratio of Legionnaires? disease among
delegates compared with nondelegates.
c. State in words the meaning of this measure.
d. Calculate the cumulative incidence difference of Legionnaires? disease among
delegates compared with nondelegates.
e. State in words the meaning of this measure.
f. Calculate the attributable proportion of Legionnaires? disease among
delegates.
g. State in words the meaning of this measure.
4. The incidence rate of migraine headaches was 1.5/100 person-years among overweight
women and 1.0/100 person-years among normal weight women. Using only this
information, state and explain your reasoning on whether you can calculate each of the
following measures.
a. Rate difference
b. Rate ratio
c. Attributable proportion among exposed
d. Attributable proportion among the total population.
5. Consider the following data from a British study of cigarette smoking and mortality
among male physicians (Doll R, Peto R, Boreham J, Sutherland I. Mortality in relation to
smoking: 50 years? observations on male British doctors. Br Med J. 2004;328:1519. Doi:
10.1136/bmj.38142.554479.AE). The age-standardized mortality rates (per 100,000
person-years) from lung cancer and ischemic heart disease are 249 and 1001,
respectively, among current smokers and 17 and 619 among lifelong nonsmokers.
a. Use these data to calculate the mortality rate ratio and mortality rate difference
for each disease comparing current smokers to lifelong nonsmokers.
b. Based on your answer to part a, is smoking a stronger risk factor for deaths
from lung cancer or ischemic heart disease?
c. Based on your answer from part a, does smoking have a greater public health
impact via deaths from lung cancer or ischemic heart disease? In other words,
if smoking were the cause of mortality, how many deaths from each cause
would have been averted if these individuals had never smoked?
2:03 7
..I LTE
Raminh
answer_1
a
These results mean that if 45/100000 women could b
regular physical activity, then the cases of ovarian car
be eliminated by 0.015%
Q2e
If no association exists between the diseases and the i
values, there will be a null value since there is no exp
the health outcome and hence the risk or incidence ra
would be 1.0 and on the other one also 1.0
Q3
Developed Legionnaires’ Disease
Convention Status Yes No
Delegate
Nondelegate
125
1724
759
TOTAL
1849
762
3
=
=
s/CI
Q??
Cumulative incidence
Cumulative incidence for delegates =
Cumulative incidence for non- delegates =
Q3b
Cumulative incidence ratio = CI delegates non delegates =
Q3c
The results suggest that the delegates have a higher ri
getting the disease than the non-delegates.
Q3d
It is calculated by taking the cumulative incidence in
unexposed group from the group with exposure = 0.0
= -0.0641
Q3e
This means that there is reduced risk of exposure bec
negative value of -0.0641
Q3f
The formula for this is
Where RR = Risk ratio and pe is prevalence ratio
PR = (125/1849)/(3/762)
= 0.068 / 0.0039 = 1.74
RR= Cle/Clu
– 0068/939 = 7
–
=
=
44
2:03 7
..I LTE
Raminh
answer_1
a
These results mean that if 45/100000 women could b
regular physical activity, then the cases of ovarian car
be eliminated by 0.015%
Q2e
If no association exists between the diseases and the i
values, there will be a null value since there is no exp
the health outcome and hence the risk or incidence ra
would be 1.0 and on the other one also 1.0
Q3
Developed Legionnaires’ Disease
Convention Status Yes No
Delegate
Nondelegate
125
1724
759
TOTAL
1849
762
3
=
=
s/CI
Q??
Cumulative incidence
Cumulative incidence for delegates =
Cumulative incidence for non- delegates =
Q3b
Cumulative incidence ratio = CI delegates non delegates =
Q3c
The results suggest that the delegates have a higher ri
getting the disease than the non-delegates.
Q3d
It is calculated by taking the cumulative incidence in
unexposed group from the group with exposure = 0.0
= -0.0641
Q3e
This means that there is reduced risk of exposure bec
negative value of -0.0641
Q3f
The formula for this is
Where RR = Risk ratio and pe is prevalence ratio
PR = (125/1849)/(3/762)
= 0.068 / 0.0039 = 1.74
RR= Cle/Clu
– 0068/939 = 7
–
=
=
44
Purchase answer to see full
attachment
