Question 1

In which of the following circumstances would it be more helpful to use the wheel model of epidemiology than the epidemiological triangle model?

Accepted Answer

The epidemiological triangle model of agent-host-environment is very useful, especially with single-cause infectious diseases. However, with the multiple factors involved in chronic diseases, the wheel model is more useful in analyzing and identifying the multiple variables.

Question 2

Which of the following best describes a model that demonstrates the progression of disease from prepathogenesis through disease outcome?

Accepted Answer

The natural history of disease model explains disease from prepathogenesis through resolution of the disease process. The epidemiological model involves the epidemiological triangle: agent, host, and environment. The ecosocial model emphasizes the role of evoloving macro-level socio-environmental factors to understand health and illness. The wheel model subscribes to multiple-causation rather than single-causation disease theory, and is more useful in analyzing complex chronic conditions and identifying factors that are amendable to intervention.

Question 3

Which of the following best describes the importance of discovering all of the variables that may be involved in creating a disease state in some persons?

Accepted Answer

Identifying risk factors is critical to creating or discovering specific prevention and intervention approaches that reduce chronic disease morbidity and mortality. Because some risk factors cannot be avoided, knowing other risk factors involved allows for more possibilities of preventing the problem. These variables need to be identified first so that health care providers are able to provide an explanation to persons as to why they are ill, obtain funding for research for the problem, and educate the community about the avoidance of the known risk factors.

Question 4

Which of the following has been determined to be a major variable in transmission of sexually transmitted infections?

Accepted Answer

The researchers concluded that ecosocial or contextual conditions strongly enhance sexually transmitted infection risk by increasing sexual risk behaviors and likelihood of exposure to infection. Thus, the environment has been determined to be a more important variable in sexually transmitted infections than the pathogenesis, susceptibility, and the amount of sex education provided.

Question 5

A community health nurse determined exactly how many cases of a particular disease were currently occurring in the community. Which of the following actions should the nurse take before determining what interventions should be planned?

Accepted Answer

No conclusions can really be drawn from just knowing a number. Only by converting that count to a rate and then comparing the rate with the previous rate, or with the rate in the broader environment or a similar community nearby, can any conclusions be drawn as to whether there is a problem or intervention needed. Once the rate has been calculated, the nurse will be able to share the findings with leadership, determine the resources available to intervene if necessary, and determine if the disease is a priority.

Question 6

Which of the following statements best describes why the incidence and prevalence of gonorrhea is unknown?

Accepted Answer

Morbidity rates (incidence and prevalence rates) are not available for many conditions because surveillance of many chronic diseases is not widely conducted. Furthermore, morbidity rates may be subject to underreporting when they are available. In other words, there is no responsibility to report cases of most diseases, including gonorrhea. Information is only available related to conditions where care providers are required to report that specific condition or where those affected die and mortality data are available.

Question 7

In a particular community, the rate of new cases of diabetes and the rate of new cases of flu during the month of January were precisely the same. Which disease would have the higher prevalence rate?

Accepted Answer

Diabetes would have the higher prevalence rate because it is a long-term chronic condition that typically does not decrease. Although flu might have a higher incidence rate of new cases, because flu is typically of short duration, the prevalence rate would remain low. Flu is contagious, which could increase the incidence rate but not the prevalence rate.

Question 8

An epidemiologist has written a summary of a food poisoning outbreak, including its cause and ways to prevent it from occurring in the future. Which of the following best describes what has been done?

Accepted Answer

There are two principal types of epidemiology: (1) analytic epidemiology and (2) descriptive epidemiology. Descriptive epidemiology describes the amount and distribution of disease, which may suggest possible causes. These causes can then be confirmed or corrected through more advanced methods of research.

Question 9

One hundred women received notification that their screening tests suggested that they might have a serious health problem. Which of the following actions should the nurse take to ensure that they will complete follow-up testing?

Accepted Answer

Not all positive screening results are confirmed with further diagnostic testing. The positive predictive value of a test (proportion of true positive results relative to all positive test results) is usually known for any screening test. Although one could argue that the test could be wrong, it is more therapeutic-because you want people to attend future screenings-to emphasize that screening is only suggestive than to say the screening test is inaccurate.

Question 10

Which of the following groups should be used to determine the community's pregnancy rate?

Accepted Answer

Although pregnancy is not specifically addressed, the text stresses that only those susceptible to a particular condition should be considered in the denominator. In the case of pregnancy, only women of childbearing age are susceptible.

Question 11

Two brothers played with their cousin. One brother later became quite ill, whereas the other did not. Which of the following provides the best explanation for this occurrence?

Accepted Answer

Assuming the two brothers lived in the same household, the environment and the agent or infectious organisms are the same. The only difference could be between the two brothers themselves and their genetic inheritance.

Question 12

A newspaper published an article stating that the athletic banquet at the local high school had approximately 1000 family members in attendance. Exactly 650 persons became ill within 24 hours, complaining of severe diarrhea, vomiting, and cramping. Which of the following best describes the attack rate?

Accepted Answer

Rates are calculated by the number of people with the problem over the number exposed to the problem. In this case, 650 persons out of the 1000 at the banquet complained of illness. Although this rate could be presented as an attack rate of 65%, 6.5% is incorrect.

Question 13

When trying to determine whether the swine flu outbreak was getting worse, which of the following rates should be carefully observed?

Accepted Answer

The incidence rate of new cases would be most useful for detecting short-term acute disease changes, because the swine flu duration is usually relatively short.

Question 14

Which of the following best describes the advantage of the web of causation model in comparison with the epidemiological triangle model?

Accepted Answer

Although it is a more recently created model, the web of causation model is more useful because it illustrates the complexity of relationships among causable variables. It is not easier to understand and use as it has more variables than the three (agent, host, and environment) in the epidemiological model.

Question 15

A nurse conducted a study of two skin lotions: (1) an inexpensive one and (2) an expensive one. The nurse found that there was a relative risk of 0.7 for skin sores using the inexpensive one and a relative risk of 1.2 using the expensive one. Which skin lotion should the nurse use?

Accepted Answer

A risk factor of less than one means the factor is actually protective, so the inexpensive lotion is helpful in preventing skin sores. A risk factor of more than one means the factor increases risk, so using the expensive lotion increases the probability of getting a skin lesion.

Question 16

People were very concerned about another outbreak of swine flu. All care providers were asked to report, without individual names, any new cases to the public health department for tracking. Which of the following would be most helpful for the local media to report to keep citizens informed?

Accepted Answer

As only new cases were being reported to the health department, the media could only report the ongoing incidence rate, that is, the number of new cases reported each day.

Question 17

Which of the following research studies would determine the attributable risk of a sedentary lifestyle in cardiac disease?

Accepted Answer

Attributable risk is determined by subtracting the rate of disease among nonexposed individuals (such as athletes) from the rate of disease among those exposed (the individuals with a sedentary lifestyle).

Question 18

Which of the following would be the best method to increase the positive predictive value of a screening test?

Accepted Answer

The positive predictive value is affected by what proportion of the tested population has the problem. To increase the positive predictive value, screen populations most at risk for the problem. Testing a large population at once, using a very sensitive or very specific screening test would not increase the positive predictive value of a screening test.

Question 19

A student athlete receives a screening examination before being active in school sports. Which of the following levels of prevention is being used?

Accepted Answer

Screening, because it may result in early diagnosis and treatment, is secondary prevention. Primary prevention refers to interventions that occur before the disease develops. Tertiary prevention focuses on limitation of disability and the rehabilitation of those with irreversible disease. Health prevention is not considered to be a level of prevention.

Question 20

For which of the following would a screening test be most appropriate?

Accepted Answer

It is extremely useful to the individuals concerned and society if screening can lead to early diagnosis and successful control of the disease process. There is no point in doing a screening if there is no treatment or if there is a known risk of social stigma and discrimination if it becomes known that the person has the disease. Discussion and disagreement continue as to whether genetic information should be used in family planning.

Quiz 5: Epidemiology