PU520: Principles of Epidemiology

Question 1

UNIT 1 ASSIGNMENT SLIDES

What is epidemiology?

Answer 1

The study of the distribution and determinants of health-related states or events in human populations, and the application of epidemiologic studies to prevent and control health problems.

It is the investigative arm of public health! Very population-based and very investigative-based and relies heavily on investigation, data, and statistics.

Question 2

What are the 6 characteristics of epidemiology?

Answer 2

Population focus
Distribution
Determinates
Outcomes
Quantification
Control of health problems

Question 2

What does the characteristic of population focus mean?

Answer 2

Population refers to a collection of individuals that share one or more observable personal or observational characteristics from which data may be collected and evaluated.

Ex. Common social, economic, family (marriage and divorce), work and labor force, and geographic factors. These are specific populations the focus would be on.

Question 3

What does epidemiology use to describe and analyze health-related states or events?

Answer 3

The scientific method

Study designs and statistical techniques for investigating an observable occurrence and acquiring new knowledge.

Question 3

What are the purposes and uses of epidemiology? (5)

Answer 3

Identifying etiology and risk factors
Determining the extent of disease in a population
Studying natural history and prognosis
Evaluating existing and new preventative and therapeutic measures/modes of healthcare delivery
Providing foundation for developing public policy and regulatory decisions

Question 4

What are some selected activities performed by an epidemiologist? (Free)

Answer 4

Identifying risk factors for disease, injury, and death
Describing the natural history of disease
Identifying individuals and populations at greatest risk for disease
Identifying where the public health problem is greatest
Monitoring diseases and other health-related events over time
Evaluating the efficacy and effectiveness of prevention and treatment programs
Providing information useful in health planning and decision making for establishing health programs with appropriate priorities
Assisting in carrying our public health programs
Being a resource person
Communicating public health information

Question 5

What is the definition of epidemic?

Answer 5

The occurrence of cases of an illness, specific health-related behavior, or other health-related events within a community or region clearly in excess of normal expectancy.

This excess could be 7 cases if the normal expectancy is 2. There is no magic number.

Question 6

What is a pandemic?

Answer 6

An epidemic that occurs worldwide, or over a wide area, crossing international boundaries, and usually affecting many people.

Question 7

What does the characteristic distribution mean in epidemiology?

Answer 7

The occurrence of diseases and other health outcomes within a population.

Looking at how frequently something is happening within a given population. We then can compare to other populations and identify an uneven distribution.

Question 8

What does the determinate characteristic of epidemiology mean?

Answer 8

It is a collective or individual risk factor (or set of factors) that is causally related to a health condition, outcome, or other defined characteristic. It is something that determines your health and well-being.

Question 9

What pertains to contact with a disease-causing factor or to the amount of the factor that impinges upon a group of individuals?

Answer 9

Exposures

Question 10

What are all the possible results that may stem from exposure to a causal factor?

Answer 10

Outcomes

This is often expressed as types and measures of morbidity (illness or injury due to specific disease or health outcome) and mortality (death from various causes).

Question 11

What is the characteristic of quantification refer to in epidemiology?

Answer 11

It refers to counting the cases of illness or other health outcomes.

Question 12

What denotes the use of statistics to describe the occurrence of health outcomes and measure their association with exposures?

Answer 12

The characteristic of quantification

Epidemiology is a quantitative discipline. If there is no hard data, it isn’t epidemiology.

Question 13

The last idea of epidemiology is the control of health problems–what does this mean? (3)

Answer 13

• Health promotion
• Alleviation of adverse health outcomes
• Prevention

Question 14

Why is epidemiology an interdisciplinary science?

Answer 14

It uses information from many fields.

Mathematics and biostatistics (for quantitative data)
History (for historical accounts of the disease and early epidemiologic methods)
Sociology (social determinates of disease)
Demography and geography (population structures and location of disease outbreaks)
Behavioral sciences (models of disease; design of health promotion programs)
Law (examining evidence to establish causality; legal bases for health policy)

Question 15

Why is epidemiology an observational science?

Answer 15

Because it capitalizes on naturally occurring situations in order to study the occurrence of disease.

For example, epidemiologists might examine and compare the frequency of lung cancer and other lung diseases among smokers and non-smokers.

Question 16

Why have epidemiologists implemented descriptive epidemiology?

Answer 16

It refers to epidemiology studies that are concerned with characterizing the amount and distribution of health and disease within a population.

Health outcomes are classified according to the variables of person, place, and time.

Question 17

What type of epidemiology examines the casual (etiologic) hypotheses regarding the association between exposures and health conditions?

Answer 17

Analytic epidemiology

The field of analytic epidemiology proposes and evaluates causal models for etiologic associations and studies them empirically.

Question 18

What is a type of experiment that is naturally occurring circumstances in which subsets of the population have different levels of exposure to a hypothesized causal factor in a situation resembling an actual experiment?

Answer 18

A natural experiment. The presence of people in a particular group is typically nonrandom.

An example of a natural experiment is the work of John Snow, discussed later in this chapter. Many past and ongoing natural experiments are relevant to environmental epidemiology. When new public health–related laws and regulations are introduced, their implementation becomes similar to natural experiments that could be explored in epidemiologic research.

For example, epidemiologists could study whether motor vehicle laws that limit texting while driving reduce the frequency of automobile crashes. Other examples of natural experiments that have evolved from laws are the addition of fluoride to the public water supply in order to prevent tooth decay and the requirement that children wear safety helmets while riding bicycles.

Question 19

What accounted for disease outbreaks before Hippocrates’ time?

Answer 19

Supernatural explanations.

In about 400 BCE, Hippocrates suggested that environmental factors such as water quality and the air were implicated in the causation of diseases. He authored the historically important book On Airs, Waters, and Places.

Question 20

Who was Paracelsus (1493–1541)?

Answer 20

Paracelsus was one of the founders of the field of toxicology, a discipline that is used to examine the toxic effects of chemicals found in environmental venues such as the work-place.

Question 21

Who was John Graunt (1620–1674)?

Answer 21

His work recorded descriptive characteristics of birth and death data, including seasonal variations, infant mortality, and excess male over female mortality.

Graunt is said to be the first to employ quantitative methods to describe population vital statistics by organizing mortality data in a mortality table. Because of his contributions to vital statistics, Graunt has been called the Columbus of statistics.

Question 22

Who was Ramazzini (1633–1714)?

Answer 22

Bernardino Ramazzini is regarded as the founder of the field of occupational medicine.

The father of occupational medicine is also considered to be a pioneer in the field of ergonomics, by pointing out the hazards associated with postures assumed in various occupations.

His book highlighted the risks posed by hazardous chemicals, dusts, and metals used in the workplace.

Question 23

Who was Sir Percival Pott (1714–1788)?

Answer 23

A London surgeon, is thought to be the first individual to describe an environmental cause of cancer. In 1775, Pott made the astute observation that chimney sweeps had a high incidence of scrotal cancer (in comparison with male workers in other occupations.

Following his conclusions about the relationship between scrotal cancer and chimney sweeping, Pott established an occupational hygiene control measure—the recommendation that chimney sweeps bathe once a week.

Question 24

Who was Edward Jenner (1749–1823)?

Answer 24

Jenner’s findings regarding his development of a vaccine that provided immunity to smallpox were published. Jenner had observed that dairymaids who had been infected with cowpox (transmitted by cattle) were immune to small-pox.

Question 25

Who is the father of epidemiology and why?

Answer 25

Jon Snow.

For example, Snow believed that the disease cholera was transmitted by contaminated water and was able to demonstrate this association.

At the time, The Dutchman Anton van Leeuwenhoek had used the microscope to observe micro-organisms (bacteria and yeast). However, the connection between microorganisms and disease had not yet been ascertained.

Question 26

What was the miasmatic theory of disease?

Answer 26

It held that “… disease was transmitted by a miasm, or cloud, that clung low on the surface of the earth. ”This theory was applied to malaria, among other diseases.

Question 27

Who was William Farr (1807–1883)?

Answer 27

Among Farr’s contributions to public health and epidemiology was the development of a more sophisticated system for codifying medical conditions than that which was previously in use.

Also noteworthy is the fact that Farr used data such as census reports to study occupational mortality in England.

In addition, he explored the possible linkage between mortality rates and population density, showing that both the average number of deaths and births per 1,000 living persons increased with population density (defined as number of persons per square mile).

Question 28

Who was Robert Koch (1843–1910)?

Answer 28

The German physician Robert Koch verified that a human disease was caused by a specific living organism.

He isolated the bacteria that cause anthrax (Bacillus anthracis) and cholera (Vibrio cholerae). One of his most famous contributions was identifying the cause of tuberculosis (Mycobacterium tuberculosis)

Question 29

Scottish researcher Alexander Fleming (1881–1955) discovered what?

Answer 29

Penicillin. It became widely available at the end of World War II.

Question 30

What are the different uses of epidemiology?

Answer 30

Historical use - documents the pat-terns, types, and causes of morbidity and mortality over time.

Community Health Use - “To diagnose the health of the community and the condition of the people, to measure the true dimensions and distribution of ill-health in terms of incidence, prevalence, disability and mortality; to set health problems in perspective and define their relative importance; to identify groups needing special attention.

Health Services Use - “to study the working of health services with a view to their improvement. Operational (operations) research translates knowledge of (changing) community health and expectations in terms of needs for services and measure [sic] how these are met.

Risk Assessment Use - “to estimate from the group experience what are the individual risks on average of disease, accident and defect, and the chances of avoiding them.

Disease Causality Use - “To search for causes of health and disease by computing the experience of groups defined by their composition, inheritance and experience, their behaviour [sic] and environments.

Question 31

What is the epidemiologic transition?

What transition coincides with epidemiologic transition?

Answer 31

It describes a shift in the patterns of morbidity and mortality from causes related primarily to infectious and communicable diseases to causes associated with chronic, degenerative diseases.

Demographic transition - a shift from high birth rates and death rates found in agrarian societies to much lower birth birth and death rates in developed countries.

Question 32

What is defined as a type of study of the placement of health services in a community and the optimum utilization of such services?

Answer 32

Operations research.

Epidemiology helps to provide quantitative information regarding the availability and cost of healthcare services. Epidemiologic studies aid planners in determining what services are needed in the community and what services are duplicated unnecessarily.

Epidemiologic methods can provide inputs into cost-benefit analyses, which balance cost issues against quality of services in order to maximize cost effectiveness.

Question 33

What is disease management?

Answer 33

This term refers to a method of reducing healthcare costs by providing integrated care for chronic conditions (e.g., heart disease, hypertension, and diabetes). With the implementation of the 2010 Affordable Care Act, epidemiologic methods will be germane to healthcare quality and efficiency.

Question 34

What is risk?

Answer 34

The probability of an adverse or beneficial event in a defined population over a specified time interval.

Question 35

What is the difference between risk and risk factor?

Answer 35

The risk factor is an EXPOSURE that is associated with a disease, morbidity, mortality, or another adverse health outcome.

The risk is the probability of the adverse health outcome.