Chapter 09 - Epidemiological Applications EVOLVE
Which of the following tools are used in analytic epidemiology? Select all that apply. A Cohort study B Case-control study C Cross-sectional study D Clinical trials E Community trials
ANS A, B. C Analytic epidemiology deals with the factors that influence the observed patterns of health and disease and increase or decrease the risk of adverse outcomes. Analytic study designs include cohort studies, case-control studies, and cross-sectional studies. In experimental or intervention studies, the investigator initiates a treatment or intervention to influence the risk or course of disease. These studies test whether interventions can prevent disease or improve health. Clinical trials and community trials are examples of experimental studies.
A business executive develops symptoms of the flu 1 day after returning by air from a cross-Atlantic business trip that ran for 2 consecutive stressful 10-hour days. This individual's development of flu symptoms illustrates the relationship between: A host and agent. B host, agent, and environment. C risk and causality. D morbidity and disease.
ANS B Epidemiologists understand that disease results from complex relationships among causal agents, susceptible persons, and environmental factors. These three elements—agent, host, and environment—are called the epidemiologic triangle. Changes in one of the elements of the triangle can influence the occurrence of disease by decreasing or increasing a person's risk for disease. The associations between risk and causality, morbidity and disease do not demonstrate the relationship to the development of flu.
Twenty people attended a church picnic the previous weekend. By Monday, four individuals exhibited symptoms of food poisoning. On Tuesday, the nurse in community health records the addition of two new cases. The incidence rate would be: A two new cases divided by 16 at risk. B two new cases divided by 20. C six cases divided by 20. D four cases divided by 16.
ANS A An incidence rate quantifies the rate of development of new cases in a population at risk, whereas an incidence proportion indicates the proportion of the population at risk that experiences the event over some period of time (Rothman, 2012). The population at risk is considered to be persons without the event or outcome of interest but who are at risk of experiencing it. People who already have the disease or outcome of interest are excluded from the population at risk for this calculation because they already have the condition and are no longer at risk of developing it.
A breast cancer screening program screened 8000 women and discovered 35 women previously diagnosed with breast cancer and 20 women with no history of breast cancer diagnosed as a result of the screening. The prevalence proportion would reflect: A current and past breast cancer events in this population of women. B newly diagnosed cases of breast cancer in this population of women. C past breast cancer events in this population of women. D the population of women that had no evidence of breast cancer.
ANS A The prevalence proportion is a measure of existing disease in a population at a particular time (i.e., the number of existing cases divided by the current population). A prevalence proportion is not an estimate of the risk of developing disease, because it is a function of both the rate at which new cases of the disease develop and how long those cases remain in the population. In this example, the prevalence of breast cancer in this population of women is a function of how many new cases develop and how long women live after the diagnosis of breast cance
Clinical medicine and epidemiology differ from each other in the major aspect of: A practice focus. B health monitoring. C determinants of health and disease. D evaluation of interventions.
ANS A Epidemiology is the study of populations to monitor the health of the population, understand the determinants of health and disease in communities, and investigate and evaluate interventions to prevent disease and maintain health. Epidemiology focuses on populations, whereas clinical medicine focuses on the diagnosis and treatment of disease in individuals. Epidemiology studies populations to determine the causes of health and disease in communities and to investigate and evaluate interventions that will prevent disease and maintain health. Epidemiologic methods are used extensively to determine to what extent the goals of Healthy People 2020 (US Department of Health and Human Services, 2010) have been met and to monitor the progress of those objectives not fully met at present.
Nurses in community health often use epidemiology because in the community it is often difficult to control the environment. Which of the following statements demonstrates an epidemiologic strategy for monitoring disease trends? A A nurse in community health conducts an education class for clients newly diagnosed with diabetes. B A nurse in community health investigates a breakout of whooping cough in a local middle school. C A nurse in community health organizes a health fair at the community health center. D A nurse in community health participates on a county school board that addresses student health issues.
ANS B Nurses are a key part of the interdisciplinary team in community settings and often use epidemiology to look at health and at disease causation and how to both prevent and treat illness. Nurses use epidemiology in the community to examine factors that affect the individual, family, and population group because it is more difficult to control these factors in the community than in the hospital. Community health nurses who conduct education classes, organize health fairs, and address student health issues are using prevention strategies.
One of the basic concepts in epidemiology is the concept of risk. Risk refers to the: A prevalence of an event occurring. B probability that an event will occur within a specified time period. C population most likely to develop a disease. D rate of development of new cases.
ANS B Risk refers to the probability that an event will occur within a specified time period. A population at risk is the population of persons for whom there is some finite probability (even if small) of that event occurring. Incidence rates and proportions measure the rate of new case development in a population and provide an estimate of the risk of disease.
A nurse is concerned about the accuracy of the PPD test in identifying cases of TB exposure for follow-up chest x-ray. The nurse's concern is addressing the validity measure of: A reliability. B sensitivity. C specificity. D variation.
ANS B Validity of a screening test is measured by sensitivity and specificity. Sensitivity quantifies how accurately the test identifies those with the condition or trait. Sensitivity represents the proportion of persons with the disease whom the test correctly identifies as positive (true positives). High sensitivity is needed when early treatment is important and when identification of every case is important. Reliability is the consistency of repeating a measure and is affected by variation in results. Specificity indicates how accurately the test identifies those without the condition or trait.
Analytic epidemiology differs from descriptive epidemiology because it searches for: A "when" of disease patterns. B "where" of disease patterns. C "why" of disease patterns. D "who" of disease patterns.
ANS C Descriptive epidemiology describes the distribution of disease, death, and other health outcomes in the population according to person, place, and time—the who, where, and when of disease patterns. Analytic epidemiology, on the other hand, searches for the determinants of the patterns observed—the how and why of disease patterns.
A nurse in community health who teaches a client with asthma to recognize and avoid exposure to asthma triggers and assists the family in implementing specific protection strategies such as removing carpets and avoiding pets is intervening at the level of: A assessment. B primary prevention. C secondary prevention. D tertiary prevention.
ANS C Primary prevention refers to interventions that promote health and prevent the occurrence of disease, injury, or disability. Interventions at this level are aimed at individuals and groups who are susceptible to disease but have no discernable pathology (state of prepathogenesis). In this case, the client has already has asthma, so the nurse teaches the client to recognize and avoid exposure to asthma triggers. This is an example of secondary prevention. Health screenings are at the core of secondary prevention. Tertiary prevention includes interventions aimed at limiting disability and interventions that enhance rehabilitation from disease, injury, or disability. Assessment is a component of epidemiology.
