Epidemiology Assignment: Questions and Answers

This assignment provides answers to various epidemiology questions including research question, causal diagram, incidence rate, prevalence, cumulative incidence rate, and person-time incident rate.

Running head: EPIDEMIOLOGY 1
Epidemiology
Name
Institution

EPIDEMIOLOGY 2
Epidemiology
Assignment 1
1. Epidemiologists are interested in learning about:
All of the above
2. Diseases that are always present in a community, usually at a
relatively low constant
frequency are classified as having an endemic pattern
3. Which of the following terms best applies to this situation? Epidemic
4. Research Question
What is the difference in daily calorie intake between male and female medical students of
Northern Ontario School of Medicine?
5. Causal Diagram

EPIDEMIOLOGY 3
The exposure in this case is the carbohydrates and the outcome is obesity. When consumption of
carbohydrates is high then the chances of being obese also increase.
Physical activity is associated with obesity such that engaging in physical activity reduces the
risks associated with obesity.
Gender is associated with the amount of food consumption which is also related to obesity.
Level of carbohydrates intake may also determine the level of physical activity.
6. Temporal relationship means that the exposure must occur before the outcome for
causality to be established.
7. Criteria not required to define confounder
The confounder is the result of an error
8. Which of the following causes of death is more likely to lead to a higher proportion of
years of potential life lost in Canada?
Cerebrovascular diseases (stroke)
9. Incidence rate
Total number of new active cases=2+16+64
¿ 82
Person-months of observation¿ ( 250−50 )=2 00
IR= 82
200 =0.41

EPIDEMIOLOGY 4
¿ 41 per 100 p ers ons−month
10. Point prevalence
number of cases at baseline=50
prevalence= 50
250 ×100
¿ 20 %
11. Period prevalence
total number of cases=82+ 50=132
prevalence= 132
250 ×100
¿ 52.8 %
12. What is the exposure of interest?
Cancer incidence
13. What is the outcome of interest?
Cancer prevalence
14. What is the population being studied?
Patients with type 2 Diabetes living in Finland
15. What is the total duration of the period of observation?
16 years

EPIDEMIOLOGY 5
16. Overall hypothesis
The presence of type 2 diabetes mellitus increases the chances of having cancer.
17. Incidence rate
¿ 74063
428326 =0.1729
¿ 17.3 cancer cases per 100 p ers ons− years
18. For which cancer site does the risk seems higher?
Liver
19. Potential confounder
The confounder is associated with the exposure of interest.
20. Method used to adjust for confounder
Direct standardization
21. Prevalence
t otal number of cases=50
p revalence= 50
1000 ×100
¿ 5 %
22. Cumulative incidence rate
number of outcomes of interest =50+75=125

EPIDEMIOLOGY 6
cumulative incidence= 125
1000 =0.125
¿ 12.5 %
23. Person-time incident rate
total number of new cases=75
person years of observation=950 ×5
¿ 4750
incident rate= 75
4750 =0.0158
¿ 15.8 HIV cases per 1000 persons− year
24. Why were women who tested positive for HIV excluded from the
study population?
The reason is due to the fact that they do not meet the inclusion criteria that ensure that subjects
are feasible for follow for a prolonged period.
25. True
26. True
27. False

EPIDEMIOLOGY 7