Topic 1 - Introduction Flashcards

1
Q

Who was Hippocrates? What theories did he develop?

A

Hippocrates was among one of the first physicians to document his observations in medicine.
Titled the father of medicine
b/c he wrote and thought about people’s health.
Spent time thinking of blood, phlem, black bile or feces, yellow bile in relation to liver and linked it to hot, cold, etc.
People thought in this way until the 1800s.

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2
Q

Describe the theory of multiple interacting causes.

A

–> Multiple Interacting Causes
* Replaced with ‘miasma’ theory
- Epidemics – e.g. Black Death aka bubonic plague, cholera, etc.
* Environmental Filth
- “Bad Air” / “Night Air”
- upto ca. 1880s

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3
Q

Who was Edward Jenner? What did he do?

A
  • Edward Jenner (1749 - 1823)
  • “Father of Immunology”
  • 1770s developed the first vaccine
  • Studied cowpox and smallpox

Demonstrated you can vaccinate against infectious diseases. Idea that moved away from miasmas.

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4
Q

Who was Edward Chadwick? What did he do?

A
  • Edwin Chadwick (1800 - 1890)
  • Lawyer in 1830
  • Assistant Commissioner on the 1834 “Poor Law”
  • Dissolved, but continued to work on issues of
    sanitation amongst the poor
  • Registration Act (1836)
  • Kept track of deaths (and causes)
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5
Q

What was Edward Chadwick’s role in the Typhus outbreak in London in 1838? What were the consequences of his actions?

A
  • Typhus outbreak in London in 1838
  • Chadwick convinced Poor Law Board to lead an inquiry
  • Edwin Chadwick’s reports led to:
  • 1848 Public Health Act
  • 1852 Metropolitan Water Act

The industrial revolution –> people working in awful conditions, poor, etc.
1820s/1830s –> people in poor health. Edwin chadwick was a lawyer at the time and was involved in helping poor people; Started keeping track of deaths.
He kept a map and reported what people were dying from to classify them.

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6
Q

Who was Florence Nightingale? What did she do?

A
  • Florence Nightingale (1820 - 1910)
  • “Mother of modern Nursing”
  • 1854 joined the British Camps
    from the Crimean War
  • More British soldiers were dying
    from disease than from wounds
  • “Within 6 months of her arrival in
    Scutari [hospital in Turkey], the
    mortality rate dropped from 42% to
    2.2%.”
  • Insisted on adequate lighting, diet,
    hygiene, and activity.

British troops wounded in crimea were being moved to turkish hospitals. Nightingale noticed more british soldiers were dying from disease more often than wounds. Mortality dropped once she arrived.

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7
Q

Who was John Snow? What did he do?

A
  • John Snow (1813 - 1858)
  • “Father of Epidemiology”
  • Physician in London
  • Skeptical of the Miasma theory that was predominant up until this time.
  • Published essay: “On the Mode of Communication of Cholera” in 1849
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8
Q

List the years in of the major cholera outbreaks in London. How many people died in each outbreak?

A
  • Major cholera outbreaks in London
  • 1 st – 1831 : 6,536 deaths
  • 2 nd – 1848-49 : 14,137 deaths
  • 3 rd – 1854 : …“about to happen”
  • Index Case: August 30th = new case of cholera in london.

Main through process: cholera communicated through water.

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9
Q
A

Dot = house with cholera
Marked water pumps
Center pump = problem
Removed handle from pump and stopped an outbreak of cholera without ever demonstrating real cause of disease. He just linked water consumption with cholera.

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10
Q

What was John Snow’s “Grand Experiment”?

A

2 companies: red = lambeth (provide water through houses either through pumps or directly to houses), green = southwark and vauxhall. Different companies = different water sources. People who lived in overlap, luck of the draw in terms of who supplied your water.
Both of them took water from river. Main difference = law that told them to move water source b/c maybe water from sewage/ocean –> gross that people drank from it. Red = moved source of water up river. Southwark did not move water source. 440,000 people monitored.

More people served by green got cholera.

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11
Q
A
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12
Q

What happened in the 1880s?

A

Robert Koch and Louis Pasteur
Focused on pathogens and infectious agents.

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13
Q

Who was Robert Koch? What did he do?

A

Up until the 1880s, there was no understanding as to what caused cholera.

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14
Q

Describe Hamburg cholera outbreak via miasma theory and organism theory.

A

Miasmas versus new scientific way of thinking. When the 5th pandemic of cholera started in 1881, hit europe in 1892. Max = all about miasmas and bad airs. Dont’ need to do anything b/c rich people are clean and poor people are not. Peter Koch = science.

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15
Q

Describe the cholera outbreak in New York in 1892.

A

ship from hamburg –> new york
no cholera in america at the time
Applied koch’s approaches. Had amazing results.

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16
Q

The 1950s was dubbed the “Chronic Disease Era” - Why?

A

A lot of these chronic diseases do not have causal agents.
What risk factors are associated with these diseases?

17
Q

What tools have evolved since the 1970s that help epidemiologists? What has remained the same?

A
  • Epidemiological trends since the 70s…
  • Concepts of causation are the same!
  • New
  • Modeling tools
  • Hierarchical structure (Ecological Studies)
  • Spatial Analysis
  • Computers and Databases
  • Data mining and machine learning
  • Mapping / Surveillance information
  • Genetic information
  • Advancement in diagnostic techniques

Microfluidic technology –> 96 assays on 96 samples.

18
Q

How does the oxford dictionary define epidemiology?

A
  • Oxford English Dictionary (2009)
    “That branch of medical science which treats of epidemics.”
19
Q

How does Schwabe (1977) define epidemiology?

A

the study of disease in populations”

20
Q

How does Martin (1987) define epidemiology?

A

“the study of frequency, distribution, and determinants of health and disease in
populations”

21
Q

How does Kenneth Rothman (2002) define epidemiology?

A

“the study of the distribution and determinants of disease frequency”

22
Q

What are the key components of epidemiology?

A

Collecting animals (sampling) and are reducing the population to a representation of that population. Measure risk factors, exposure, others of interest. All of this in mind is to understand relationship with disease (if any of these factors are related to disease).

bias –> error
Trying to be as accurate as possible.

23
Q

How do we know something (risk factor) causes/prevents disease?

A

“a cause is any factor that produces a change in the severity or frequency of the outcome”

24
Q

What would be the IDEAL (and impossible) scenario?

A

…Counterfactual concept
Being able to track your subjects habits every single day to determine the root cause, but that is not possible.

25
Q

Explain the difference between association and causation.

A

Association is only a quantitative measure of the strength of the relationship between an exposure and outcome
* Think statistical correlation…

26
Q

List the criteria for causation based on Hill’s Criteria (1965)

A

*1. Strength of Association
Big vs Small risk difference
*2. Consistency
Repeatable?
3. Time Sequence
*4. Dose-Response
5. Plausibility
Biologically sensible
6. Experimental evidence (study design)

We measure a lot of these criteria. It allows us to quantify how much of a variable is responsible for causation.

27
Q

What is the definition of a necessary cause? Give an example.

A
  • A factor that must be present for the disease to occur
  • e.g. Koch’s postulates with agents and disease
28
Q

What is the definition of a component cause? Give an example.

A
  • Component causes
    1. Sufficient causes
  • If certain factors are present, the disease always follows
  • Very few factors are truly sufficient…
    –> Usually, several factors in combination constitute a sufficient cause
  • For example Bovine Respiratory Disease (BRD) – ‘disease complex’
  • Bacterium: namely Mannheimia homolytica
    • Pasteurella multocida, Histophilus somni, and Mycoplasma bovis
  • Virus: namely Bovine Respiratory Syncytial Virus (BRSV)
  • Parainfluenza (PI-3), Bovine Viral Diarrhea Virus (BVDV), and Bovine Herpesvirus (BHV-1)
  • Set of stressors: weaning, transport, inclement weather
29
Q

Describe the causal web model.

A