BIOM30001 Lecture Notes - Lecture 4: Adolphe Quetelet, John Snow, Nosology
Definitions
For example, the incidence of thyrotoxicosis during 1982 was 10/100000/year in Barrow-in-Furness compared
with 49/100000/year in Chester
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Incidence: rate at which new cases occur in a population during a specified period
The prevalence of persistent wheeze in a large sample of British primary school children surveyed during 1986 was
approximately 3 per cent, the symptom being defined by response to a standard questionnaire completed by the
children's parents.
•
Prevalence is an appropriate measure only in such relatively stable conditions, and it is unsuitable for acute
disorders.
•
Prevalence : proportion of a population that are cases at a point in time.
For example, smoking increases your chances of developing colon cancer. Therefore, smoking is a risk factor for
colon cancer.
•
Other times, there's nothing you can do about the risk. It just exists. For example, people 50 and older are more
likely to develop colon cancer than people under 50. So, age is a risk factor for colon cancer. (In fact, it's the
number one risk factor.)
•
Risk Factor: something that increases your chances of getting a disease. Sometimes, this risk comes from something you
do.
Measuring diseases and conditions in populations was foundational to the emergence of modern medicine.
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Pluralist medicine regarded every individual’s sickness to be unique to that individual in personal circumstances,
time and place.
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Tuberculosis after French Revolution
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Invention of stethoscope to compare symptoms between patients
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Autopsy after death to confirm disease
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From early C19th, new mathematical methods were employed to compare cases and determine that different
people were afflicted with the same disease.
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Vital statistics ➜‘thermometer of health’ The bookkeeping of life & death
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Adolphe Quetelet (Belgian, 1796-1874): ‘social physics’ or ‘social statistics’ = systematic disease patterns.
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Concept of the ‘average man’ who could be measured in large numbers and expressed mathematically —average
mental, moral and physical characteristics
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Population Health As A Diagnostic Aid: defining disease (nosology)
Investigating WHERE, WHEN and WHO fell sick helped discover what was causing the disease; what the RISKs
were.
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Dr John Snow, father of infectious disease epidemiology, mapped cases of cholera in Soho London in 1854 and
traced the source back to the water pump in Broad Street.
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Next he demonstrated that people in the same suburb who bought water from different water companies were at
risk if the water was collected down river.
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Why are THESE people sick NOW & in THIS PLACE?
PROBLEM: a chronic condition triggered by weight gain
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WHO has metabolic syndrome
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WHERE do they live?
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WHAT are the characteristics of the people who develop it? Age/Sex/Income/Ethnicity/Social Status/
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Is there something significant about where they live? Services/shops
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HOW widespread is it? (PREVALENCE)
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Is it changing? Getting worse?
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Creation of new high % groups all start in the east and spread outwards
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Is it something in the environment? The food itself? Let’s look at the evidence in the US prepared by the Centre
for Disease Control
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Metabolic Syndrome
4: Metabolic syndrome as a social and political sickness -
A Population Perspective
Tuesday, 4 August 2015
10:50 AM
Frontiers Page 1
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Frontiers Page 2
Document Summary
4: metabolic syndrome as a social and political sickness - Incidence: rate at which new cases occur in a population during a specified period. For example, the incidence of thyrotoxicosis during 1982 was 10/100000/year in barrow-in-furness compared with 49/100000/year in chester. Prevalence : proportion of a population that are cases at a point in time. The prevalence of persistent wheeze in a large sample of british primary school children surveyed during 1986 was approximately 3 per cent, the symptom being defined by response to a standard questionnaire completed by the children"s parents. Prevalence is an appropriate measure only in such relatively stable conditions, and it is unsuitable for acute disorders. Risk factor: something that increases your chances of getting a disease. Sometimes, this risk comes from something you do. For example, smoking increases your chances of developing colon cancer. Therefore, smoking is a risk factor for colon cancer. Other times, there"s nothing you can do about the risk.
