COH 315 – Principles of Epidemiology
COH 315 – Principles of Epidemiology
Calculations and Interpretations: Answer the following questions in the space provided. Show
all of your work.
1. Evidence of an increased risk of lung cancer associated with cigarette smoking was sought by Doll and Hill. In one study, 649 lung cancer cases were matched by age, and gender to 649 controls; 647 of the cases and 622 of the control had a history of smoking cigarettes.
a. Name the type of study.
b. Create the appropriate 2X2 table for the study. (2 points)
Lung Cancer Controls
Smokers
647
2
Total
27
649
Nonsmokers
622
649
c. Calculate the appropriate measure of association for the study. (4 points)
d. Interpret the results. (2 points)
2. In another study, the smoking habits of 34,445 male physicians were obtained by mailed questionnaires. Deaths among these physicians over the subsequent years were identified though contact with the office of the Registrar General. The death rates from lung cancer of these physicians classified by smoking habits were :
Standardized Death Rates per 1000 Persons Aged 35 or More per
Year
Nonsmokers
0.07
Cigarette Smokers
0.96
a. Name the type of study. (2 points)
b. Calculate the Relative Risk for smokers as compared to nonsmokers. (6 points)
c. Interpret the results (2 points)
Annual Death Rates per 100,000 Persons
Exposure Category
Lung Cancer
Heavy Smokers
Nonsmokers
Coronary Heart Disease
166
7
599
422
a. Calculate the relative risk from Lung Cancer Mortality for Heavy Smokers compared to
non smokers. ( 4 points)
b. Calculate the attributable risk of Lung Cancer from smoking. (4 points)
c. Interpret the results. (2 points)
d. Calculate the percent attributable risk of Coronary Heart Disease due to smoking (4
points)
e. Interpret the results. (2 points)
3. Convert the following incidence rates to attributable risk using the additive model: (5
points)
Incidence Rates
Relative Risks
Factor A
Factor A
_
Factor B –
+
3.0
_
+
9.0
_____________________________________
__________________________________
+
15.0
21.00
4. Calculate the concordance rate for the following data: (5 points)
Twin 1
Has Leukemia
Twin 2
Does Not Have Leukemia
Has Leukemia
14
1
Does Not Have Leukemia
26
36
