Assignment
1. Most of the time, epidemiologic researchers confront a problem that has a clear etiologic basis.
True
False
2. The existence of a dose-response relationship, that is, an increase in disease risk with an increase in the amount of exposure, does not support a view that an association is a causal one.
True
False
3. When the prevalence of the disease is much greater than the incidence, the duration of the disease is long and the case fatality is low.
True
False
4. The major categories of descriptive epidemiologic variables are person, place, and time.
True
False
5. A cross-sectional study allows the demonstration of a time sequence.
True
False
6. Randomized controlled community trials may be used in special situations such as simple intervention studies.
True
False
7. The attributable risk is defined as the ratio of the incidence of the disease among exposed individuals to the incidence among non-exposed individuals.
True
False
8. The purpose of matching in a case-control study is to select the controls in such a way that the control group has the same distribution as the cases with respect to certain confounding variables.
True
False
9. Specificity refers to the ability of a screening test to identify only non-diseased individuals who actually do not have the disease.
True
False
10. Reliability relates to the ability of a measure to be consistently reproducible, regardless of its accuracy.
True
False
11. A secondary attack rate is used to show the spread of infectious diseases in a household.
True
False
12. Eradication of smallpox was successful because of a program to immunize its primary reservoir, the green monkey in central Africa.
True
False
13. Herd Immunity refers to the protection of a population against an infectious disease when a large proportion of individuals are immune through their vaccinations or past infections.
True
False
14. The case fatality rate is the same thing as the mortality rate for a disease.
True
False
15. Incubation period refers to the time between the start of the infection and the beginning of the period of communicability.
True
False
16. Certain diseases, e.g., the common cold, can occur more than once in a stated period of time. Repeated cases of the disease have NO effect upon incidence rates.
True
False
17. Sensitivity refers to the ability of a screening test to identify correctly all screened individuals who have a disease.
True
False
18. Outbreaks in infectious disease can occur only when there are changes in the host and the environment.
True
False
19. If a disease is fatal, virulence can be measured by the case fatality rate.
True
False
20. The case fatality rate of a disease is defined as the number of deaths due to the disease divided by the number of cases of the disease during a specified time period.
True
False
21. In cohort studies, information can usually be obtained on the whole spectrum of morbidity and mortality.
True
False
22. One of the main purposes of descriptive epidemiology is to aid in the creation of hypotheses.
True
False
23. The proportional mortality ratio is defined as the mortality due to a specific cause during a time period divided by the mortality due to all causes during the same time period.
True
False
24. The criterion of plausibility refers to the existence of a dose-response relationship.
True
False
25. A prerequisite for using direct age adjustment is that the age-specific death rates in the study population must be stable.
True
False
26. An abrupt drop in mortality due to a specific disease from one year to the next is most likely due to:
Incorrect listing of cause of death by the physician on the death certificate.
Incorrect coding assignment according to the International Classification of Disease (ICD) system.
Both of the above.
A change in the International Classification of Disease (ICD) system.
All of the above.
27. In case-control studies, the odds ratio is used as an estimate of the relative risk. In order for this approximation to be reasonable, some conditions must be met. Which of the following conditions is NOT necessary in order to use the odds ratio to estimate the relative risk?
Controls are representative, with respect to exposure, of the population to which you want to generalize your results.
The event (disease) under study is rare in the population.
The exposure in question is rare in the population.
Cases are representative of all cases.
28. Intervention designs are utilized to explore:
The etiology and natural history of the disease.
The differences in exposure frequency that may be associated with one group having the disease of interest.
The efficiency of prevention measures.
All of the above
29. You are investigating the role of physical activity in heart disease and you suggest that physical activity protects against having a heart attack. While presenting this data to your colleagues, someone asks if you have thought about confounders such as factor X. This factor X could have confounded your interpretation of the data if it:
Is a factor for some other disease, but not heart disease.
Is a factor associated with physical activity and heart disease.
Is a part of the pathway by which physical activity affects heart disease.
Has caused a lack of follow-up of test subjects.
30. Which of the following is NOT a method for controlling the effects of confounding in epidemiologic studies?
Randomization.
Stratification.
Matching.
Blinding.
None of the above.
31. Sensitivity and Specificity of a screening test refer to its:
Reliability.
Validity.
Yield.
Repeatability.
None of the above.
All of the above.
32. A new blood test has been developed to screen for disease Z. Researchers establish 50 units as a cut point above which a test is considered positive and thereby indicative of disease. The test's manufacturers determine that the test's sensitivity is unacceptably low. However, the manufacturers are not concerned with the specificity and do not want the cost of the test to rise. How can they improve the sensitivity of the test?
Test each person's blood twice.
Lower the cut point below 50 units.
Raise the cut point above 50 units.
They cannot improve this test and should begin work developing a new test.
33. Healthy worker effect refers to the observation that:
Exercise on the job causes workers to become healthy and gain years of life.
Healthy persons are more likely to gain employment than unhealthy persons.
Unemployed persons tend to have lower mortality than employed persons.
All of the above.
34. An attack rate is an alternative incidence rate that is used when:
Describing the occurrence of food borne illness or infectious diseases.
The occurrence of disease among a population at risk increases greatly over a short period of time.
The disease rapidly follows the exposure during a fixed time period.
All of the above.
None of the above.
35. The lowest dose at which a particular response may occur:
Threshold.
Latency.
Synergism.
None of the above.
36. Which of the following statements describes the person-environment fit model?
Discrepancy between husband and wife in social and education status.
Goodness of fit between the characteristics of the person and environment.
Stressors that result from the happenings in one's existence.
None of the above.
37. Selye's Concept of the general adaptation syndrome did not include:
Alarm reaction.
Stage of recovery.
Stage of resistance.
Stage of exhaustion.
38. For questions 38-40: An epidemiological survey of roller-skating accidents in Juneau, Alaska, a city with a population of 100,000, found that in the month of the survey:
Number of skaters = 12,000
Number of roller-skating accidents = 600
Total number of residents injured from roller-skating = 1,800
Total number of deaths from roller-skating = 90
Total number of deaths from all causes = 900
The crude death rate in Juneau in that month was:
90/600
90/10,000
90/1,800
90/900
39. The cause-specific mortality rate from roller-skating was:
90/600
90/100,000
90/1,800
90/900
40. The proportional mortality ratio due to roller-skating was:
90/600
90/100,000
90/1,800
90/900
41. Which of the following reasons might account for place variation in disease?
Concentration of racial or ethnic groups within an area
Genetic and environment interactions
Influence of climate
Presence of environmental carcinogens
B & E
A & C
All of the above
42. The uses of epidemiology include:
Searches of determinants (causes of disease)
Estimation of individual risks and chances of contracting disease
Evaluation of health services
All of the above
43. For questions 43-47: As an epidemiologist you are going to investigate the effect of a drug suspected of causing malformations in newborn infants when the drug in question is taken by pregnant women during the course of their pregnancy. As your sample you will use the next 200 single births occurring in a given hospital. For each birth a medication history will be taken from the new mother and from her doctor. [N.B: these mothers are considered to have been followed prospectively during the entire course of their pregnancy because a complete and accurate record of drug use was maintained during pregnancy.]
The resultant data are: Forty mothers have taken the suspected drug during their pregnancy. Of these mothers, 35 have delivered malformed infants. In addition, there are 10 other infants born with malfunctions.
The relative risk (or risk ratio) is:
10
12
14
16
18
44. What is the exposure status variable(s) in the study?
Drug usage
Type of hospital
Obstetrical methods
Malformations
None of the above
All of the above
45. What is the disease status variable in the study?
Drug usage
Type of hospital
Obstetrical methods
Malformations
None of the above
46. What is the disease incidence in the study?
40/160
35%
45/200
45%
47. These results prove that:
Pregnant women with single births are more likely to be prescribed medications during pregnancy.
Newborns with malformations are more likely to be single births.
Women should never be allowed to take any medications during pregnancy.
All of the above.
None of the above.
48. Case control studies are among the best ways to study diseases of:
High prevalence
High validity
Low case fatality
Low prevalence
49. The population etiologic fraction of a particular disease from Factor X alone is five times greater than that from factor Y alone. If the relative risk associated with factor X is 2, and with factor y is 20, which of the following statements is true?
The risk of developing the disease is greater in those exposed to factor X only, than in those exposed to factor Y only
Fewer persons are exposed to factor Y than to factor X
The proportion of the disease in the population attributable to factor Y is greater than that attributable to factor x
More persons are exposed to factor Y than to factor X
The risk of developing the disease for persons exposed to factor Y is five times greater than for persons exposed to factor X
50. In a case-control study of the effect of exposure E on disease D, an Odds Ratio of 2.0 means:
E causes D.
D causes E.
There are twice as many cases as controls.
There are 2 exposed cases for every unexposed control.
None of the above.
Part 2
Each of the following two essays is worth 25 points of your Final exam grade.
Important note: Carefully read and follow the submission instructions below. You are to submit Essay I (sections a and b) and Essay II together in a single Word document, making sure to label the sections clearly. You are to submit section c of Essay I in a PowerPoint document, if possible, to the digital dropbox. If you do not have PowerPoint, you must include section c in the Word document with the rest of the Essay exam answers.
Essay I: Lesson:
Assume you are an epidemiologist and affiliated with academia. You have been asked to teach one session (one hour) of basic epidemiologic concepts to:
The target population: will be potential graduate students interested in your graduate program in Epidemiology.
The purpose: of the presentation is to educate the target population on epidemiology facts and principles and to help them better understand what Epidemiology is about, its concepts and applications. Give examples of current Public Health issues to illustrate the need and application of Epidemiologic concepts.
In this, you are asked to provide the following:
a. Purpose & Objective: State a purpose and 3 to 4 objectives for developing an educational lesson on basic concepts of Epidemiology. You can refer to what you learned in PUBH 6145.
b. Notes: Provide two to three paragraphs of notes summarizing what you will cover in your teaching session.
c. Slides: Present the lesson in a PowerPoint format with titles, figures and other illustrative techniques. Please provide no more than 25-30 slides.
Essay II:
Prepare an answer to the following question. It should not exceed 4 to 5 single-spaced pages in 12 pt. font.
Based on your readings and understanding regarding the association between exposure to PPA and stroke (readings from term paper) and from other sources (Medline searches), you are required to present a CAUSAL argument based on the Bradford Hill Criteria of causality to show that exposure to PPA in cough and cold preparation (mostly over the counter medications) is causally or not causally linked to having stroke.
Clarification: There is a stronger argument linking PPA in diets pills to Hemorrhagic Stroke (HS) but you are asked here to show whether exposure to PPA from cough/cold remedies (not diet pills) is linked or not linked causally to HS.
Please submit your argument based on the following outline:
a- Animal studies
b- Controlled clinical trials
c- Strength of association
d- Consistency of finding with other information
e- Specificity
f- Temporal Relationship
g- Dose Response
h- Biological Plausibility
i- Biologic Coherence
j- Experimentation
k- Analogy.