This document provides instructions for an exam in the course "Msc. Applied Human Nutrition" on the topic of "Nutrition Epidemiology". The exam consists of three sections: Section A has 30 multiple choice questions, Section B has 5 short answer case scenario questions, and Section C has additional case scenario questions. The exam is designed to evaluate students' understanding of key epidemiological concepts, study designs, measures of disease frequency, and their ability to apply these concepts to analyze epidemiological data and studies.

1. MAKERERE UNIVERSITY
SCHOOL OF FOOD TECHNOLOGY, NUTRITION AND BIO-ENGINEERING
END OF SEMESTER EXAMS
Course: Msc. Applied Human Nutrition
Module: Nutrition Epidemiology
Date:
Time:
Duration:
Instructor: Ms Pamelah Kihembo
Instructions:
This paper consists of two sections. Section A has 30 multiple choice questions. Circle the most
correct answer. Section B has five case scenario questions. Please, choose four questions from this
section. Questions from this section carries equal marks.

2. SECTION A
1. Epidemiology is defined as the
a) Most failed course at the university
b) The study of the distribution and determinants of disease and the application of this
knowledge in the management of health related events
c) The study of diseases and their interpretation
d) The study of epidemics
2. Diseases are not randomly distributed. They occur
a) In certain places
b) At certain times
c) Among certain people
d) All the above
e) None of the above
3. The epidemiological triad consists of
a) Host
b) Antigen
c) Time
d) None of the above
4. Trends analysis is an example of which of the following study designs
a) Cohort study
b) Case control study
c) ecological study
d) Randomized controlled trial
5. The initial studies establishing maternal diethylstilbestrol (DES) intake as a cause of
vaginal adenocarcinoma in female offspring were case-control studies. This was probably
largely because:
a) A couple of decades ago cohort studies hadn't been invented
b) A woman taking DES was always rare.
c) The disease outcome is rare
d) The investigators had probably just happened to have a number of cases in their practices
6. In a case-control study of alcohol intake and bladder cancer, cases and matched controls
are each interviewed by interviewers who are not blinded as to whether the subject is a case
or a control. Many of the .interviewers are in fact convinced that drinking alcohol is a cause
of bladder cancer. Is this likely to represent a bias?
a) No, because the interviewers can't affect whether the subjects are considered cases or
controls; that's already decided
b) Yes, but it's hard to predict the direction of the bias.

3. c) Yes, and would predispose to a rejection of the null hypothesis.
d) Yes, and would predispose to a failure to reject the null hypothesis
7. Dr. Smith performed a research study where he concluded that children with pets at home
show more empathy than those without pets at home. Which of the correlation coefficients
below would fit this significant association?
a) 0.85
b) 0.00*
c) 0.65
d) – 0.45
8. Dr. Yang does a study in which she observes one hundred children over a
period of six years, noting changes over time. Which type of research design
is Dr. Yang using?
a) Quasi experiment
b) Case control study
c) Retrospective cohort cross sectional
d) Longitudinal, prospective cohort
e) Experiment
9. Which of the following is NOT a benefit of randomized control trials?
a) RCTs minimize attrition bias
b) RCTs minimize selection bias
c) RCTs are easy to conduct
d) RCTs can be designed by experimenters
e) Both a and c
10. A cohort study is which type of study?
a) Observational
b) Longitudinal
c) Analytical
d) All the above
e) Only b
11. Which of the following is not a challenge of conducting a cohort study
a) Loss of participants during follow up
b) Expensive
c) Large sample sizes
d) Variances in background of participants
12. The study population for a case control study contains
a) Only the cases
b) Only the controls
c) Both cases and controls

4. d) Only the exposed
e) All the above
13. The case control study lay out involves
a) Define the source population, select sample based on disease status, assess past
exposure history
b) Select based on disease status, randomize, assess past exposure history
c) Select participants based on exposure history, follow them up in time, assess
disease status
d) Select participants based on intervention status, randomize, follow them up in
time, establish disease status
14. Which of the following are frequency measures?
a. Birth rate
b. Incidence
c. Mortality rate
d. Prevalence
15. All proportions are ratios, but not all ratios are proportions.
a. True
b. False
Use the following choices for Questions 16-18
1. Ratio
2. Proportion
3. Incidence proportion
4. Mortality rate
16. ____
# women in Country A who died from lung cancer in 2004
# women in Country A who died from cancer in 2004
17. ____
# Women in Country A who died from lung cancer in 2004
# women in Country A who died from breast cancer in 2004
18. ____
# women in Country A who died from lung cancer in 2004
estimated # women living in Country A on July 1, 2004
19. Vaccine efficacy measures are:
A. The proportion of vaccines who do not get the disease

5. B. 1 − the attack rate among vaccines
C. The proportionate reduction in disease among vaccines
D. 1 − disease attributable to the vaccine
Write True or False for each of the following statements
Write true or false for each of the statements.
20. Randomization in RCTS means that the sample included in the study are randomly selected
from the population.
21. Randomization ensures that there is no allocation bias
22. A double blind trial avoids assessment bias
23. A double blind trial always involves the use of a placebo
24. A control group must always be given a placebo
25. All clinical trials are randomized trials
26. The most appropriate measure of association in cohort studies is the relative risk
27. We can determine incidence in case control studies
28. When conducting a cohort study, we start with people with disease and ask establish their
exposure history
29. All observational studies are analytical in nature
30. Case control studies can be used to study many exposures
SECTION B. SHORT ANSWER QUESTIONS (10 marks)
For each of the following scenarios, identify whether the study is a descriptive or analytical
study:
1. A researcher wants to estimate the proportion of students in Guelph who are infected with
the mumps virus, so they sample all registered students at secondary schools in Guelph and
determine how many were infected.
2. You want to determine whether the proportion of puppies with canine parvovirus differs
between puppies living on farms and puppies living in urban households (e.g., city centres).
3. You hypothesize that cholesterol levels differ between people who retired early (i.e., before
age 65) and those who retired on time (age 65 or later), so you enroll both groups of people
and record their cholesterol levels and test whether there is a difference.
4. An environmental group routinely collects information on air pollution in each major city
and reports on their findings.
For each of the following scenarios, identify whether it is an observational study or
experimental study:
5. A researcher wants to investigate the association between coffee drinking and good grades
on midterms. She assigns half of the class to drink 2 cups of coffee right before the midterm

6. and tells the other half to drink 2 cups of water. Then, she compares the midterm grades
from each group to see if there is an effect.
6. A farmer wants to determine if a new medication is effective at treating lameness in their
cows. They give the new medication to 100 cows and compares their frequency of lameness
to 100 cows who are using the old medication.
7. A veterinarian wants to investigate the association between dog breed and food allergies.
She collects information from dog owners about their breed of dog and whether the dog
has allergies. She then uses this information to compare frequency of food allergies
between different dog breeds.
Select all of the following studies that are experimental (as opposed to observational).
8. A study to assess the impact of vitamin intake on the development of cancer, by collecting
dietary information from food diaries.
9. A study to assess the impact of vitamin intake on the development of cancer, by randomly
allocating some patients to vitamin supplementation.
10. A comparison of the outcome of patients registered at a single hospital who were treated
with either drug A or drug B. Data were collected from routine hospital notes. received
drug A or drug B as clinically indicated.
SECTION C: CASE SCENARIO QUESTIONS
QUESTION ONE
With examples, differentiate between the following terms
a) Incidence and Incidence rate (2 marks)
b) Point prevalence and Period prevalence (2 marks)
c) Mortality rate and case fatality rate (2 marks)
d) Infant mortality rate and child mortality rate (2 marks)
e) Maternal mortality rate and maternal mortality ratio (2 marks)
ii) The following is a classic 2 by 2/epidemiologic table
Exposure status Diseased/cases Controls Total
Exposed A B a+b
Not exposed C D c+d
Total a+c b+d a+b+c+d
a) What do the following represent? ( 1 mark each)
i. a/c

7. ii. b/d
iii. a/(a+b)
iv. c/(c+d)
v. (a+c) / (a+b+c+d)
iii) a) What is the formula for calculating the odds ratio using the table above? (1 mark)
b) What study design utilizes the odds ratio as a measure of disease frequency? (1 mark)
c) What do the following odds ratios mean? 1, 1.5, 0.5 (3 marks)
QUESTION TWO:
1. The study to determine the effect of nutrition education on dietary behaviors was conducted
among HIV positive patients at Mulago Hospital. In this study, participants were randomly
selected and distributed to be either in the intervention group or control group. Those in
the intervention arm were given nutrition counselling on each visit while the participants
in the control arm were left to continue with the hospital program of no nutrition education.
Please, use this information to answer the following questions.
a) Nutrition counselling and dietary behaviors will be measured as which variables
and why? (2 marks)
b) Which category/class of variables are they? (2 marks)
c) Which study design is this? (1 mark)
d) What are the characteristics/key features of this study design? (1 mark)
e) What are its advantages and disadvantages? (6 marks)
Figure 3.1 represents 10 new cases of illness over about 15 months in a population of 20
persons. Each horizontal line represents one person. The down arrow indicates the date of
onset of illness. The solid line represents the duration of illness. The up arrow and the cross
represent the date of recovery and date of death, respectively.

8. a) Calculate the incidence rate from October 1, 2004, to September 30, 2005, using the
midpoint population (population alive on April 1, 2005) as the denominator. Express
the rate per 100 population (3 marks)
b) Calculate the point prevalence on April 1, 2005. Point prevalence is the number of
persons ill on the date divided by the population on that date. On April 1, seven persons
(persons 1, 4, 5, 7, 9, and 10) were ill. (2marks)
c) Calculate the period prevalence from October 1, 2004, to September 30, 2005. The
numerator of period prevalence includes anyone who was ill any time during the period.
In Figure 3.1, the first 10 persons were all ill at some time during the period. ( 2 marks)
QUESTION THREE:
What are the key features of ecological studies in epidemiology? (3 marks)
Under what conditions do we conduct ecological studies? (3 marks)
With examples. Explain the different types of ecological studies (3 marks)
Which measure of disease frequency is used to interpret ecological studies? (1 mark)
Explain the meaning of the term ecological fallacy. How can it be overcome? (2 marks)
Explain the Hill’s criteria for causation (8 marks)
QUESTION FOUR
a) Explain the key features of Randomized controlled trials? ( 6 marks)
b) With examples, explain the 5 major biases that are likely to result from RCTs and how they
can be prevented (10 marks)
c) A study randomly allocated HIV infected mothers to breastfeeding or formula feeding and
looked at the differences in the transmission rate of HIV to infants. The study found that
the risk of transmission was 16.2% higher in the breastfeeding arm and that 44% of HIV
infection in the breastfeeding arm was due to breastfeeding.

9. d) Calculate the incidence of HIV among the Breastfed and non- breastfed children? ( 1 mark)
e) What is the relative risk of HIV transmission between the two groups? (1 mark)
f) What percentage of HIV transmission can be attributed to Breast feeding? (1 mark)
g) Explain your results to a political activists in e and f above to your local NGO director
implementing an HIV support program. (1 mark)