[2.2] Epidemiology in Public Health Flashcards
Environmental and host factors influence the development of disease
Hippocrates 400 BC
Who wrote the essay entitled “On Airs, Waters, and Places”
Hippocrates 400 BC
Published analysis of mortality data in 1662
John Graunt 1662
First to quantify patterns of birth,
death, and disease occurrence
John Graunt 1662
Noted disparities between males and females, high infant mortality, urban/ rural differences, and seasonal variations
John Graunt 1662
Systematically collecting and analyzing Britain’s mortality statistics
William Farr 1800
Father of Modern Vital Statistics and Surveillance
William Farr 1800
Reporting to health authorities and the general public
William Farr 1800
Father of Field Epidemiology
John Snow 1854
Conducted studies of cholera outbreaks to discover the cause of disease and to prevent its recurrence
John Snow 1854
What century is the British Doctor’s Study about smoking causes lung cancer
19th and 20th Century
Smoking decreases life span up to ____
10 years
What century was the Framingham Heart Study
19th and 20th Century
What study says “Cardiac health is influenced by lifestyle, environmental factors, and inheritance “
Framingham Heart Study
Origin of the term Risk Factor
Framingham Heart Study
The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems
Epidemiology
Major role of epidemiology is to provide a clue to changes that take place over time in the health problems presenting in the community
Changing Patterns
Populations are facing a rise of non-communicable diseases generally among affluent sections while communicable diseases and under-nutrition still persist among the poorest sections of the society
Double Burden of Disease
Populations suffer from backlog of common infections, undernutrition, and maternal mortality, the emerging challenges of noncommunicable diseases (NCDs), such as cancer, diabetes, heart disease, and mental illness, and the problems directly related to globalization, like pandemics and the health consequences of climate change.
Triple Burden of Disease
Infectious microorganism
Pathogen
Bacteria, Virus, Parasite
Pathogenicity
(ability to cause disease)
Virulence
(severity of a disease)
Chemical and Physical
causes of injury
Agent
Human exposure and
susceptibility
Age and Sex
Behaviors and Practices
Genetic composition,
nutritional and
immunologic status
Host
Extrinsic factors that affect the agent and
opportunity for exposure
Environment
If a high enough proportion of individuals in a population are resistant to an agent, then those few who are susceptible
will be protected by the resistant majority.
Herd Immunity
Refers to the progression of a disease process in an individual over time
Disease Timeline
The stage of subclinical disease, extending from the time of exposure to onset of disease symptoms, is usually called
the [1]_______ for infectious diseases and the [2]_________ for chronic diseases
[1] Incubation period
[2] Latency period
The onset of symptoms marks the transition from subclinical to clinical. Ranging from mild to severe or fatal.
Spectrum of disease
Persons who are infectious but have a subclinical disease or individuals who harbors the organism but are not infected. This person, however, can still infect others
Carriers
Carrier of Salmonella, she worked as a cook in New York City and caused 10 typhoid fever outbreaks
Mary Mallon
Refers to a disease that occurs infrequently and irregularly
Sporadic
The habitual presence of a disease within a given geographical area. The usual occurrence of a given disease within an area.
Endemic
The occurrence in a community or region of a group of illnesses of similar nature, clearly in excess of normal expectancy, and derived from a common or from a propagated source
Epidemic
Refers to a worldwide epidemic
Pandemic
Group of persons are all exposed to an infectious agent or a toxin from the same source.
Common-source outbreak
If the group is exposed over a relatively brief period, so that everyone who becomes ill does so within one incubation period
Point-source outbreak
Case-patients have been exposed over a period of days, weeks, or longer
Continuous common-source outbreak
Results from transmission from one person to another. Usually, transmission is by direct person-to-person contact
Propagated outbreak
Cases occur over more than one incubation period
Propagated outbreak
Epidemics have features of both common source epidemics and propagated epidemics
Mixed epidemics
What are the Steps in the Epidemiological Approach
Step 1: Immediately
Step 2: Disease Control Steps
Step 3: EPidemiological Research
Step 4: Calculate the attack rate
Step 5: Why did it happen
Step 6: Prevention of recurrence
What Step is:
Determination of the population at risk
What Step is:
Mobilization of the health sector, invoking of an “emergency/ disaster plan”
Step 1 (Immediately)
What Step is:
Isolation and treatment of cases
Notification
Search for and quarantine of contacts
Step 2 Disease Control Steps
Separates sick people with a contagious
disease from people who are not sick
Isolation
Separates and restricts the movement of
people who were exposed to a contagious
disease to see if they become sick
Quarantine
What step answers WHO? WHAT? WHEN? WHERE?
Step 3 Epidemiological Research
What step is:
Attack Rate
Food-Specific Attack Rate
Secondary Attack Rate
Step 4 Calculate the attack rate
Based on the type of epidemic and its graph, determine the incubation period
Combine this with the diagnosis, and search back to the common cause
Step 5 Why did it happen
Follow up: set up control program
- Agent
- Transmission Route
- Host
Step 6 Prevention of recurrence
Reporting of specific disease cases
Active surveillance:
Routine health statistics
Passive surveillance
Associations on population levels may not reflect associations on individual levels.
Ecologic Studies
Incorrectly assuming that an association on a population level reflects an association on an individual
Ecologic Fallacy
A type of observational study that analyzes data from a population, or a representative subset, at a specific point in time.
A cross-sectional
In ________ investigators enroll individuals who do not yet have the health outcomes of interest at the beginning of the observation period, and they assess exposure status for a variety of potentially relevant exposures
cohort studies
The Framingham Heart Study is an example of _____ cohort study
Prospective Cohort Studies
The Nurses Health Study is an example of ______ cohort study
Prospective Cohort Studies
Cohort: Employees of a tire manufacturing company
Retrospective Cohort Study
Used to determine if there is an association between an exposure and a specific health outcome. These studies proceed from effect (e.g. health outcome, condition, disease) to cause (exposure)
Case-control studies
Research model used to estimate causal relationships without random assignment
Quasi-experimental Design
2 examples of Quasi-experimental Design
Time series design and Pretest Posttest Design
What Kind of Design:
Measurements are taken multiple times before and after a treatment to observe changes over time
Time series Design
Participants are measured before and after receiving a treatment to assess changes
Pretest posttest Design
Similar to prospective cohort studies, in design in that studies with or without a given exposure are followed over time to compare the incidence of the outcome of interest
Intervention Studies
New treatments are tested for the effectiveness in treating diseases
Therapeutic Trials
Healthy or high-risk individuals are tested to determine whether a treatment prevents disease
Preventive Trials
