Epidemiology Attributable Risk Quiz
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Questions and Answers

What is the formula for calculating attributable risk?

  • Incidence in non-exposed minus incidence in exposed
  • Incidence in exposed plus incidence in unexposed
  • Incidence in total divided by total population
  • Incidence in exposed minus incidence in unexposed (correct)

    • In the cohort study scenario, how many lung cancer cases occurred among smokers?

  • 50
  • 30
  • 20
  • 40 (correct)

    • What is the attributable risk calculated from the cohort study results given the following: 40 smokers developed lung cancer and 10 non-smokers developed lung cancer?

  • 50
  • 40
  • 10
  • 30 (correct)

    • How does the incidence of lung cancer in smokers compare to that in non-smokers in this study?

    <p>Smokers have a higher incidence than non-smokers</p> Signup and view all the answers

    In the case control study scenario, what primary statistical measure would be assessed?

    <p>Attributable risk</p> Signup and view all the answers

    What is the primary characteristic of a carrier of a disease?

    <p>Harbors a pathogen without symptoms</p> Signup and view all the answers

    Which term describes an exaggerated immune response to harmless substances?

    <p>Hypersensitivity</p> Signup and view all the answers

    What does the term 'virulence' refer to in the context of infectious diseases?

    <p>The degree of damage a pathogen can cause</p> Signup and view all the answers

    Which of the following is NOT an element of the chain of infection?

    <p>Pathogen replication</p> Signup and view all the answers

    What is defined as the ability of a pathogen to enter, survive, and multiply in a host?

    <p>Infectivity</p> Signup and view all the answers

    Which term describes diseases that occur infrequently and irregularly in a population?

    <p>Sporadic</p> Signup and view all the answers

    How does a portal of exit function in the chain of infection?

    <p>It is the method by which the pathogen leaves the reservoir</p> Signup and view all the answers

    What does immunogenicity refer to in relation to pathogens or vaccines?

    <p>The ability to provoke an immune response</p> Signup and view all the answers

    What does an odds ratio greater than 1 indicate?

    <p>Exposure increases the likelihood of developing a disease.</p> Signup and view all the answers

    In which type of study is relative risk primarily used?

    <p>Cohort studies.</p> Signup and view all the answers

    What does an odds ratio of 1 imply?

    <p>No association between exposure and disease.</p> Signup and view all the answers

    What is the primary purpose of using an odds ratio in epidemiology?

    <p>To compare exposed individuals to non-exposed individuals.</p> Signup and view all the answers

    What is the formula for calculating the incidence rate?

    <h1>new cases divided by total person-time at risk</h1> Signup and view all the answers

    How is attributable risk defined?

    <p>The proportion of risk attributable to exposure.</p> Signup and view all the answers

    What does a high mortality rate for a disease typically indicate?

    <p>A need for improved treatment or prevention strategies</p> Signup and view all the answers

    What does an odds ratio less than 1 suggest?

    <p>Exposure decreases the likelihood of disease.</p> Signup and view all the answers

    Which statement accurately describes relative risk (RR)?

    <p>A RR greater than 1 indicates increased risk due to exposure</p> Signup and view all the answers

    Which of the following is a characteristic of a case-control study?

    <p>It compares individuals with a specific condition to those without.</p> Signup and view all the answers

    What is the formula for calculating relative risk?

    <p>$\frac{A/(A+B)}{C/(C+D)}$</p> Signup and view all the answers

    How is mortality rate typically expressed?

    <p>Number of deaths per 1,000 people per year</p> Signup and view all the answers

    What does morbidity rate measure?

    <p>The prevalence of illness in a population</p> Signup and view all the answers

    What is the relationship of an odds ratio (OR) to exposure and outcome?

    <p>It compares the odds of an outcome in the exposed vs. unexposed groups</p> Signup and view all the answers

    How is the crude death rate calculated?

    <h1>of deaths times 1,000 divided by midpoint population</h1> Signup and view all the answers

    Which of the following best represents risk in epidemiology?

    <p>The proportion of individuals who develop a disease over time</p> Signup and view all the answers

    What does the incidence rate measure in epidemiology?

    <p>The number of new cases of a disease in a specific period</p> Signup and view all the answers

    How is prevalence defined in epidemiology?

    <p>The proportion of a population that has a disease at a given time</p> Signup and view all the answers

    Which of the following is NOT a measure of central tendency?

    <p>Variance</p> Signup and view all the answers

    What is the formula for calculating prevalence?

    <p>P = Number of Cases / Population Size × 100</p> Signup and view all the answers

    What does the mode represent in a dataset?

    <p>The most frequently occurring value</p> Signup and view all the answers

    In a dataset with the values 10, 20, 30, 30, and 50, what is the median?

    <p>30</p> Signup and view all the answers

    Which statement about rates in epidemiology is correct?

    <p>Rates compare the frequency of events to the population at risk</p> Signup and view all the answers

    When calculating the mean, which operation is used?

    <p>Adding all values and dividing by the number of values</p> Signup and view all the answers

    What is the definition of an epidemic?

    <p>An unusual and unexpected occurrence of a disease.</p> Signup and view all the answers

    Which of the following best describes endemic diseases?

    <p>Diseases that consistently occur at a predictable rate in specific areas.</p> Signup and view all the answers

    What characterizes a pandemic?

    <p>It is an outbreak affecting multiple countries and continents.</p> Signup and view all the answers

    What is innate immunity?

    <p>The body's natural first line of defense present from birth.</p> Signup and view all the answers

    How is acquired immunity developed?

    <p>After exposure to a specific pathogen or through vaccination.</p> Signup and view all the answers

    What role do immunoglobulins play in the immune response?

    <p>They are antibodies produced by the immune system to neutralize pathogens.</p> Signup and view all the answers

    What is herd immunity?

    <p>When a significant portion of a population becomes immune to a disease, reducing its spread.</p> Signup and view all the answers

    Which of the following statements about immune response is true?

    <p>It is the body's defense mechanism activated upon recognizing foreign substances.</p> Signup and view all the answers

    Study Notes

    Epidemiology

    • Objectives: Define terms related to infectious diseases; construct tables & figures for epidemiology data; calculate disease frequency & infection rates; interpret key components of epidemiologic data; analyze epidemiological data; preparation of tables & graphs (graphs, histograms, population pyramids, bar charts, pie charts, scatter diagrams, maps).
    • Epidemic: An unusual and unexpected occurrence of a disease.
    • Endemic: Constant presence and/or usual frequency of a disease or infectious agent within a specific geographic area or population. Predictable rate in that area. (Example: Malaria in Sub-Saharan Africa).
    • Pandemic: An outbreak of a disease on a global scale, affecting multiple countries and continents, often causing widespread illness. (Example: Covid-19).
    • Immunity: The body's ability to resist or defend against infection, disease, or other biological invaders.
      • Innate (Natural) Immunity: Body's first line of defense, present from birth, providing non-specific protection.
      • Acquired (Adaptive) Immunity: Developed after exposure to a specific pathogen, through infection or vaccination. Provides targeted, long-lasting defense. (Example: Measles vaccine providing acquired immunity) .
    • Immune Response: The body's defense mechanism activated upon recognizing foreign substances (antigens) like pathogens.
    • Herd Immunity: When a significant portion of a population becomes immune to a disease, reducing its spread and protecting non-immune individuals.
    • Immunoglobulin: Antibodies produced by the immune system to neutralize pathogens like bacteria and viruses.
    • Host Response: The way a person's body reacts to an invading pathogen, either by immune defenses or inflammatory processes.
    • Hypersensitivity: An exaggerated or inappropriate immune response to a harmless substance, such as in allergies.
    • Infection: The invasion and multiplication of microorganisms (bacteria, viruses, parasites) within the body causing disease.
    • Infectivity: The ability of a pathogen to enter, survive, and multiply in a host.
    • Pathogenicity: The ability of a microorganism to cause disease in a host.
    • Carrier: An individual who harbors a pathogen but does not exhibit symptoms of the disease, potentially causing an outbreak or continued transmission. (Example: Asymptomatic carrier of Salmonella Typhi).
    • Virulence: The degree of damage a pathogen can cause to the host.
    • Immunogenicity: The ability of a substance (pathogen or vaccine) to provoke an immune response.
    • Sporadic: Refers to diseases that occur infrequently and irregularly within a population.

    Elements of the Disease Process-Chain of Infection

    • Infectious Agent: The pathogen (e.g., bacteria, virus).
    • Reservoir: Where the pathogen lives (e.g., humans, animals).
    • Portal of Exit: How the pathogen leaves the reservoir (e.g., respiratory droplets).
    • Mode of Transmission: How the pathogen spreads (e.g., airborne, direct contact).
    • Portal of Entry: How the pathogen enters a new host (e.g., through broken skin).
    • Susceptible Host: An individual who can contract the disease due to weak or absent immunity.

    Measurements & Their Calculations

    • Ratios, Proportions, Incidence rates, Prevalence rates, Demographic rates
    • Relationships between predictive value and disease prevalence

    Frequency

    • The fundamental epidemiological measure is the frequency with which an event (disease, injury, death) occurs in the population.
    • Usually expressed as a count. Examples include tables, bar charts, line graphs, etc.
    • Incidence and prevalence are essential to epidemiology.
    • Rates are the frequency of events in a defined time period divided by the average population at risk.

    Measures of Central Tendency- Mean Mode Median

    • Mean, Median, and Mode: Measures of central tendency. Summarize a dataset, identifying the central or typical value.
      • Help summarize and interpret large datasets.
      • Mean (average): arithmetic average representing the typical value. Calculated by dividing the sum of all values in a dataset by the number of values. (Examples: average age at diagnosis, average number of cases, average exposure levels in a population).
      • Median: middle value in a dataset when values are ordered. If even number of values, average of the two middle values.
      • Mode: Value that occurs most frequently in a dataset.

    Interpreting Key Components of Epidemiologic Data

    • Prevalence: Proportion of a population having a particular disease or condition at a specific point in time or over a specified period.
    • Proportions: Fractions in which the numerator is included in the denominator. Prevalence is calculated by (# of cases/# of people in the population) X 100).
    • Incidence Rate: The number of new cases of a disease or condition in a specific period within a population at risk. Unique from prevalence in how numerator and denominator use different measurement units for rates, i.e., new observed cases per unit of observation time period divided by the total person-time at risk.
    • Mortality Rate: Number of deaths due to a particular cause per unit of population, usually per 100,000 people per year. (Crude death rate formula = # of deaths/midpoint population x 1000 population.
    • Crude Birth Rate, Infant Mortality, Age Specific and Maternal Mortality, Neonatal Mortality Rate: Calculations for these are provided in the handout.
    • Morbidity Rate: Frequency or rate of disease within a population. Measures burden of illness and provides insight into health needs (ex: high Morbidity Rate for diabetes shows need for better management).

    Interpreting Key Components of Epidemiologic Data

    • Risk: Proportion of persons unaffected at the beginning of a study period but who undergo a risk event (death, disease, injury) during the study period.
    • Relative Risk (RR): Measures the risk of a health event among those exposed to a risk factor compared to those not exposed. A RR greater than 1 indicates increased risk of exposure; less than 1 indicates decreased risk.
    • Odds Ratio (OR): Measure of association between exposure and outcome. Calculated by comparing odds in exposed vs unexposed groups. A greater than 1 suggests an association; less than 1 suggests protective effect of exposure.
    • 2x2 Table: Used in case-control and cohort studies, showing exposure and outcome. The OR and RR are calculated from the values in this table.
    • Cohort Study: Prospective or retrospective observational study following a group of individuals over time to see how exposure to a risk factor affects disease or outcome.
    • Case-Control Study: Retrospective study comparing individuals with a specific condition to those without, to assess if exposure to a risk factor is associated with the condition.
    • Attributable Risk: The difference in health outcome rate between exposed and unexposed groups, indicating the attributable proportion of risk to the exposure.

    Scenario

    • Cohort study scenario: In a cohort study, among 100 smokers, 40 developed lung cancer; and among 100 non-smokers, 10 developed lung cancer. Calculate and interpret results.
    • Case-control study scenario: Among 100 smokers, 40 developed lung cancer; and among 100 non-smokers, 10 developed lung cancer. Calculate and interpret results.
    • Calculate Attributable Risk: Calculate the attributable risk from the scenarios above. Interpret the results.

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    Epidemiology Measurements and Calculations Handout 3 PDF

    Description

    Test your knowledge on the concept of attributable risk in epidemiology. This quiz covers critical questions related to cohort studies, including lung cancer incidence among smokers and non-smokers, as well as essential statistical measures in case-control studies. Enhance your understanding of how to calculate and interpret attributable risk in public health research.

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