Epidemiology Practice Questions

42 multiple-choice questions on Epidemiology for paramedic and EMT students, from Chapter 3 (Public Health). Read each question, pick your answer, then tap Show answer to check it and read the explanation.

42 practice questions

1. Epidemiology is the study of:

   1. A. Microorganisms that cause infection
   2. B. How disease is distributed in populations
   3. C. Diagnosis and treatment of individual patients
   4. D. How medications act within the body
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   Answer: B. How disease is distributed in populations

   It tells public health where to aim its efforts. It also examines the factors that influence that distribution.

2. Incidence refers to:

   1. A. New cases in a population over a period
   2. B. Deaths from a disease over a period
   3. C. The proportion of cases that are severe
   4. D. All existing cases at a point in time
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   Answer: A. New cases in a population over a period

   Incidence measures new risk; prevalence measures the burden already present.

3. Prevalence refers to:

   1. A. Deaths from a disease each year
   2. B. New cases arising over a period
   3. C. Cases that resolved during the year
   4. D. All existing cases at a given time
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   Answer: D. All existing cases at a given time

   A chronic disease can have low incidence and high prevalence.

4. Morbidity refers to:

   1. A. Illness, injury, or disability
   2. B. Deaths in a population over time
   3. C. Recovery from illness or injury
   4. D. Rate of births in a population
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   Answer: A. Illness, injury, or disability

   Mortality refers to death.

5. A disease constantly present at a stable level in a population is:

   1. A. Epidemic
   2. B. Pandemic
   3. C. Endemic
   4. D. Sporadic
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   Answer: C. Endemic

   An epidemic is a sharp rise above the expected level.

6. A pandemic is:

   1. A. An epidemic across many countries
   2. B. A disease that must be reported by law
   3. C. An outbreak confined to a single city
   4. D. An illness that recurs every season
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   Answer: A. An epidemic across many countries

   Scale, not severity, is what makes it a pandemic. It may span continents.

7. Surveillance in public health means:

   1. A. Close bedside monitoring of individual patients
   2. B. Police monitoring of high-crime neighborhoods
   3. C. Ongoing collection and analysis of data
   4. D. Quality review of EMS patient care reports
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   Answer: C. Ongoing collection and analysis of data

   EMS data feeds surveillance systems, including overdose and injury tracking. Its purpose is to detect patterns in health data and trigger action.

8. A risk factor is:

   1. A. A symptom that signals disease is present
   2. B. A guaranteed cause of a specific disease
   3. C. An unwanted side effect of a treatment
   4. D. An exposure that raises disease risk
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   Answer: D. An exposure that raises disease risk

   Risk factors may be modifiable, such as smoking, or fixed, such as age. It can be a characteristic or an exposure.

9. Years of potential life lost is a measure that emphasizes:

   1. A. Hospital costs of chronic illness
   2. B. Deaths among the oldest adults
   3. C. Deaths that occur early in life
   4. D. The prevalence of chronic disease
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   Answer: C. Deaths that occur early in life

   Injury kills the young disproportionately, so it ranks higher by this measure than by raw death counts. This highlights injury as a major public health problem.

10. The injury pyramid illustrates that:

    1. A. Injuries are rare compared with illnesses
    2. B. Most serious injuries ultimately end in death
    3. C. Only fatal injuries are worth tracking closely
    4. D. Each death reflects many lesser injuries
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    Answer: D. Each death reflects many lesser injuries

    The wide base is where prevention can have the largest effect. For every death there are many hospitalizations, emergency visits, and minor injuries.

11. The national EMS data system used to aggregate patient care records for research and surveillance is:

    1. A. CAAHEP
    2. B. NHTSA
    3. C. NEMSIS
    4. D. NREMT
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    Answer: C. NEMSIS

    Good field documentation is what makes that data usable.

12. Vital statistics include:

    1. A. Hospital admission and discharge counts
    2. B. Recorded births, deaths, and marriages
    3. C. Blood pressure, pulse, and respirations
    4. D. EMS response and transport times
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    Answer: B. Recorded births, deaths, and marriages

    Death certificate data drives much of the nation's mortality reporting. These recorded life events are used to track population health.

13. The father of modern epidemiology, John Snow, is known for:

    1. A. Tracing cholera to a London water pump
    2. B. Developing the first smallpox vaccine
    3. C. Founding the first public health agency
    4. D. Discovering the bacterium that causes cholera
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    Answer: A. Tracing cholera to a London water pump

    Removing the pump handle stopped the outbreak.

14. The epidemiologic triangle consists of:

    1. A. Patient, provider, hospital
    2. B. Host, agent, and environment
    3. C. Cause, effect, treatment
    4. D. Time, place, person
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    Answer: B. Host, agent, and environment

    Disease results from their interaction.

15. In the epidemiologic triangle, the agent is:

    1. A. The insect or animal that carries it
    2. B. The person who is affected
    3. C. The setting where exposure occurs
    4. D. The cause, such as a pathogen or energy
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    Answer: D. The cause, such as a pathogen or energy

    In injury, the agent is energy. Agents include pathogens, chemicals, and forms of energy.

16. Describing disease by time, place, and person is called:

    1. A. Experimental epidemiology
    2. B. Analytic epidemiology
    3. C. Clinical epidemiology
    4. D. Descriptive epidemiology
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    Answer: D. Descriptive epidemiology

    It generates hypotheses about cause.

17. Analytic epidemiology seeks to:

    1. A. Test treatments on individual patients
    2. B. Count cases for routine surveillance
    3. C. Describe patterns by time, place, and person
    4. D. Identify causes by comparing groups
    Show answer

    Answer: D. Identify causes by comparing groups

    Cohort and case-control studies are analytic.

18. An outbreak is defined as:

    1. A. One severe case requiring hospitalization
    2. B. Spread of disease across several countries
    3. C. More cases than expected in a group
    4. D. Any single case of a reportable disease
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    Answer: C. More cases than expected in a group

    Even two cases can be an outbreak for a rare disease. The excess is judged for a given area or group over a particular period.

19. A cluster refers to:

    1. A. Cases grouped in time or place
    2. B. A single case of an unusual disease
    3. C. The usual baseline level of a disease
    4. D. A worldwide spread of a new disease
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    Answer: A. Cases grouped in time or place

    Investigation determines whether it is an outbreak. A cluster may or may not exceed what is expected.

20. The attack rate measures:

    1. A. The average severity of the illness in cases
    2. B. All existing cases across the whole population
    3. C. Share of exposed people who become ill
    4. D. Deaths among people who are already ill
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    Answer: C. Share of exposed people who become ill

    It is useful in outbreak investigations.

21. Case fatality rate measures:

    1. A. Share of people with a disease who die
    2. B. Total deaths from all causes in a population
    3. C. All existing cases at a single point in time
    4. D. New cases arising over a defined period of time
    Show answer

    Answer: A. Share of people with a disease who die

    It reflects severity, not spread.

22. Crude mortality rate refers to:

    1. A. All deaths in a population over a period
    2. B. Deaths among infants under one year
    3. C. Deaths from one specific cause
    4. D. Deaths adjusted for age differences
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    Answer: A. All deaths in a population over a period

    Age adjustment allows fair comparison between populations.

23. Age-adjusted rates are used to:

    1. A. Mask real differences between communities
    2. B. Simplify data by merging all age groups
    3. C. Inflate the rates in younger populations
    4. D. Compare populations of differing ages
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    Answer: D. Compare populations of differing ages

    An older population has more deaths regardless of health.

24. Infant mortality rate is considered a sensitive indicator of:

    1. A. The quality of local EMS response
    2. B. Size and capacity of local hospitals
    3. C. Overall community health and access
    4. D. Rates of private insurance coverage
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    Answer: C. Overall community health and access

    It reflects maternal health, nutrition, and health care.

25. Life expectancy is:

    1. A. A fixed value determined by genetics
    2. B. The average age of a living population
    3. C. The maximum age any human can reach
    4. D. Average years expected to live from an age
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    Answer: D. Average years expected to live from an age

    It varies widely by country and community.

26. Relative risk compares:

    1. A. Risk in exposed versus unexposed groups
    2. B. Prevalence versus incidence of a disease
    3. C. Costs versus benefits of an intervention
    4. D. Rates of two unrelated diseases
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    Answer: A. Risk in exposed versus unexposed groups

    A relative risk of 2 means double the risk.

27. An odds ratio is typically used in:

    1. A. Cohort studies
    2. B. Case-control studies
    3. C. Randomized trials
    4. D. Surveillance
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    Answer: B. Case-control studies

    It approximates relative risk for rare outcomes.

28. Attributable risk refers to:

    1. A. The share of risk explained by genetics
    2. B. Disease in the exposed that is due to exposure
    3. C. The baseline risk in unexposed people
    4. D. The total risk of disease in a population
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    Answer: B. Disease in the exposed that is due to exposure

    It shows how much disease prevention could eliminate.

29. The natural history of disease describes:

    1. A. The history of how a disease was discovered
    2. B. Disease course from exposure to outcome
    3. C. Available treatment options for a disease
    4. D. The typical hospital course of a disease
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    Answer: B. Disease course from exposure to outcome

    Knowing it identifies points for intervention. It describes that course without intervention.

30. The preclinical phase of disease is:

    1. A. Disease present before symptoms appear
    2. B. The moment of first exposure to the agent
    3. C. The recovery period after successful treatment
    4. D. The period after a diagnosis has been made
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    Answer: A. Disease present before symptoms appear

    Screening targets this phase.

31. Screening tests are used to:

    1. A. Replace routine physical exams by clinicians
    2. B. Treat disease before complications develop
    3. C. Make a definitive diagnosis in sick patients
    4. D. Find disease in people without symptoms
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    Answer: D. Find disease in people without symptoms

    A positive screen requires confirmation. The disease is present but unrecognized.

32. A good screening test should be:

    1. A. Used for any condition, treatable or not
    2. B. Reserved for patients who have symptoms
    3. C. Inexpensive, regardless of what it detects
    4. D. Sensitive and aimed at treatable disease
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    Answer: D. Sensitive and aimed at treatable disease

    Screening for untreatable conditions has little value. It must also be acceptable to patients, and early treatment must change the outcome.

33. Lead-time bias refers to:

    1. A. Disease starting earlier in some groups
    2. B. Worse outcomes from delayed diagnosis
    3. C. Longer apparent survival from earlier diagnosis
    4. D. Faster treatment leading to better outcomes
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    Answer: C. Longer apparent survival from earlier diagnosis

    It can make screening look better than it is. Diagnosis comes earlier, but the actual course of disease is unchanged.

34. Sentinel surveillance uses:

    1. A. Reports from every provider in an area
    2. B. Data drawn exclusively from hospital records
    3. C. Random samples of the general population
    4. D. Selected sites reporting to monitor trends
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    Answer: D. Selected sites reporting to monitor trends

    It is efficient but may miss cases.

35. Syndromic surveillance monitors:

    1. A. Confirmed laboratory diagnoses of infection
    2. B. Test results reported by public health labs
    3. C. Symptom patterns that may signal outbreaks
    4. D. Causes of death listed on death certificates
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    Answer: C. Symptom patterns that may signal outbreaks

    EMS call data feeds some of these systems. For example, a spike in emergency visits for respiratory illness can flag an outbreak early.

36. The basic reproduction number, R0, describes:

    1. A. How severe a disease is in each case
    2. B. Share of cases that end in death
    3. C. Average number infected by one case
    4. D. Time from exposure to first symptoms
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    Answer: C. Average number infected by one case

    An R0 above 1 means the disease can spread. R0 assumes a fully susceptible population.

37. Herd immunity threshold depends on:

    1. A. The region's climate and geography
    2. B. How contagious the disease is (R0)
    3. C. The total size of the population
    4. D. The cost of the available vaccine
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    Answer: B. How contagious the disease is (R0)

    Measles requires very high coverage.

38. Injury epidemiology treats injury as:

    1. A. Predictable events with known risk factors
    2. B. Events too varied to measure reliably
    3. C. Random accidents that cannot be foreseen
    4. D. Unavoidable results of daily activity
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    Answer: A. Predictable events with known risk factors

    The word accident is avoided for this reason.

39. In injury epidemiology, the agent is:

    1. A. The vehicle involved in the crash
    2. B. The roadway and surrounding conditions
    3. C. Energy, such as mechanical or thermal
    4. D. The person who sustains the injury
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    Answer: C. Energy, such as mechanical or thermal

    Vehicles and weapons are vehicles for energy. Electrical and chemical energy count as well.

40. A risk factor differs from a cause because a risk factor:

    1. A. Always leads to the disease eventually
    2. B. Cannot be measured in a population
    3. C. Raises probability without guaranteeing it
    4. D. Is always something a person can change
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    Answer: C. Raises probability without guaranteeing it

    Smoking raises lung cancer risk without guaranteeing it.

41. Surveillance data from EMS is limited by:

    1. A. Laws that prohibit sharing EMS data
    2. B. High cost of storing patient records
    3. C. Poor documentation and missing outcomes
    4. D. The sheer volume of calls being recorded
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    Answer: C. Poor documentation and missing outcomes

    Standardized data sets address some of this. Inconsistent definitions between agencies also reduce its value.

42. Which is an appropriate use of epidemiologic data by an EMS agency?

    1. A. Ranking crews by their patients' outcomes
    2. B. Choosing destination hospitals by reputation
    3. C. Targeting prevention and resources by need
    4. D. Diagnosing individual patients on scene
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    Answer: C. Targeting prevention and resources by need

    Data should drive both prevention and operations. Epidemiology describes groups, so it cannot grade individual crews or diagnose a single patient.