Philosophical Historiography of Epidemiology.pptx

PHILOSOPHICAL
HISTORIOGRAPHY
OF EPIDEMIOLOGY
Presented by
Swastika Poudel
MPH 2023
07/01/2025 1

The real purpose of the scientific method is
to make sure Nature hasn’t misled you
into thinking you know something you don’t actually
know … If you get careless or go
Romanticizing scientific information, giving
it to flourish here and there, Nature will
soon make a complete fool out of you.
– Robert Pirsig
07/01/2025 2

INTRODUCTION
•All through history, epidemics have
ravaged human civilizations.
•The word that has been used to describe
such outbreaks, ‘epidemic’, describes
events of a kind that people would not be
satisfied merely to describe but which
they would also try to explain.
07/01/2025 3

INTRODUCTION
•The new millennium commenced with a great pandemic of a new disease,
AIDS, which decimated the population of sub-Saharan Africa and disrupted
the health and disease care resources of many other locales.
• Some other Third World countries saw a resurgence of old diseases such as
malaria and tuberculosis, in addition to new diseases.
• Indeed, it is a truism that epidemics of infectious diseases have been major
contributors to the course of history and that, in the future, humankind will
experience further ‘visitations’ of humankind’s apocalyptic horsemen.
07/01/2025
4

ORIGIN OF
MODERN
EPIDEMIOLOGY
•Modern epidemiology is relatively a recent
phenomenon. However, epidemiological enquiry
has been through centuries. Example: Greek
miasmatic theory of disease.
•Early epidemiologists broadly considered not only
infectious disease epidemics like malaria, cholera
and plague but also environmental hazards like lead
and climate.
•This is reflected in a common definition of
epidemiology as ‘the study of the distribution and
the determinants of disease frequency in human
populations, and ‘its theory and practice have been
profoundly influenced by society – by economic,
social and political developments’.
07/01/2025 5

John Graunt [1620–1674]
In his1662 classic book, Natural and Political Observations Made upon
the Bills of Mortality , reported on the socio- demographic distribution
of mortality in London and especially on the mortal consequences of
plagues.
•Inferences about mortality and fertility in the human population, noting
the usual excess of male births, the high infant mortality and the
seasonal variation in mortality.
•Distinguish two broad causes of mortality, the acute and the ‘chronic
diseases’, and to discern urban–rural differences in mortality.
07/01/2025 6

EPIDEMIOLOGIC
REVOLUTION
oNineteenth Century: Industrial Revolution in
Europe and North America
oResults in health benefits for majority of
population. However, enclosure and increasing
farm sizes were creating rural unemployment while
factory machinery rendered cottage industry
redundant.
oEpidemiologic viewpoint: two aspects of the
Industrial Revolution impacted prominently on the
health of populations-
Urbanisation and rapid long-distance
transportation
oThe crowded, unsanitary conditions in industrial
slums resulted in repeated attacks of cholera,
typhoid fever and smallpox in epidemic forms.
07/01/2025 7

•John Graunt, William Farr ([1851] 2008 ) and John Snow (1936),
Pierre Charles, Alexandre Louis [1787–1872] and Pierre Simon
Laplace [1749–1827] and Peter Johann Franck [1745–1821]
developed the concept of ‘medical police’.
•Medical police- as core of the medical system to make the care for
the health of the population a permanent subject of political
intervention, even in the absence of the traditional major causes of
mortality such as plague.
07/01/2025 8

•Peter Johann Franck’s aim was to promote health through
legislation and to enforce health laws through the state mechanisms.
For him reorganization of health authorities, hospitals and medical
schools devoid of people having nothing to eat had no meaning.
•Epidemiology, with its population perspective, ushered in a new era
of a sanitary movement influenced by the miasma theory.
07/01/2025 9

Before the miasma approach in epidemiology, contagion (the idea that specific contagia are the
sole causes of infections and epidemic diseases) was identified as the main source of disease in
populations, and quarantines were imposed on affected populations.

William Farr and John Snow
•Farr and Snow’s partnership was very fruitful and revolutionised the
application of epidemiology to public health.
• Farr explained this in terms of the miasma theory. He wrote that the
Thames’s ‘dark, turbid, dirty waters were breathing incessantly into the
vast sleeping city, tainted vapour.’
•Farr also provided tabulations of cholera mortality by source of water
supply in his1848 Cholera Report .
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11

•Based on these data, Snow formulated his hypothesis that the
cause of cholera was a self-reproducing organism excreted by the
victim of the disease and spread by fouled water supplies.
•1853–1854 outbreak: Snow proposed a test of the hypothesis by a
survey among London households which were being randomly
supplied by water companies drawing on sources with different
likelihoods of being contaminated.
•1866 report: Farr tracked the outbreak of cholera to a water
company’s careless and illegal use of unfiltered water. Farr
showed his growing awareness of the epidemic process.
07/01/2025 12

•He arrived at many key epidemiological insights that the distribution of
cholera in the population was much wider than the fatalities and even
wider than the diagnosed cases; beyond this, he postulated subclinical
forces and unaffected persons who were infected but resistant to the
disease.
•Snow changed the scientific paradigms of his times with a few brilliant
strokes – by demonstrating the plausibility of a new theory of disease
that was much more cogent and specific than any that had preceded it.
•Farr helped in the process by demonstrating, over a lifetime, the
necessity for population studies to describe states of health and to
establish the causes of health disorders and prevent them.
07/01/2025 13

John Simon [1816–1904]
•Another ardent supporter of the miasma theory of disease, was
imbued with the spirit of the environmental reform and fully
recognised the economic implications of ill health.
•Concerned with the investigation of ‘food supply, of house
accommodation, and the physical surroundings and of industrial
circumstances ’ .
•He maintained that social and economic conditions were intimately
related to greater or lesser prevalence of disease, and that these
relations should be made the subject of exact scientific investigation.
07/01/2025 14

Lambert Adolphe Jacques Quetelet [1796–1874]
•Quetelet’s ideas on ‘the average man’, for example, are clearly based
on a combination of probability theory and measurement of the
characteristics of populations.
• He believed that man could be better understood if we studied him as
a collective body rather than as an abstract individual.
•In Quetelet’s work, there was a clear signal of the great potential of
statistics for understanding the social context.
•‘Statistics to a degree became a science of social causality based on
Quetelet’s ideas of the average man’.
07/01/2025 15

Pierre Charles Alexandre Louis
•Period of ‘statistical enlightenment
•Epidemiology ‘greened’ in the ‘statistical climate of the early
nineteenth century’
•He realised that the numerical method provided an opportunity to
develop new insights into disease aetiology through the population
perspective.
•Concept of epidemiological reasoning
•For example, the germ theory was the generalisation based on the fact
that several diseases, i.e. syphilis, smallpox and cholera, had all been
shown to be caused by specific contagion.
07/01/2025 16

Claude Bernard’s [1813–1878]
•In mid-nineteenth-century, He insisted that for medicine to be truly
scientific, it must be ‘based only on certainty, on absolute
determinism, not on probability’.
•Statistics can never yield scientific truth. It was the emerging notion
that experimental study in the laboratory could potentially provide
absolute proof of, say, cause of a disease, while statistical field
studies could only demonstrate what might be the cause.
Two fundamental precepts of epidemiologic reasoning were
emerging:
recognition of the influence of the environment and of the utility
of population-level analysis
07/01/2025 17

Rudolf Virchow
•The great pioneer of cellular pathology and research scientist.
•One of the founders of the Medical Reform movement in Germany.
•He made profound contributions to public health and indeed to hospital
development.
•Virchow argued that the only way in which the health of the population
could be significantly improved was through intervention in the
determinants of health: access to resources and their distribution –
issues that were profoundly political in nature.
•Virchow gave the slogan: ‘Medicine is a social science and politics is
nothing but medicine on a grand scale.’
07/01/2025 18

Rudolf Virchow
•He stressed the importance of full employment, adequate income,
housing and nutrition and gave little attention to matters which were
purely ‘medical’ in nature.
•He was aware of the value of bacteriological research, but he could
never accept a simple causal relationship between bacterium and
disease.
•Virchow conceived the scope of public health as broadly as possible,
indicating that one of its major functions was to study the conditions
under which various social groups lived and to determine the effects
of these conditions on their health.
07/01/2025 19

Pettenkofer and Alfred Grotjahn [1869–1931]
Insisted on social factors other than hygiene and saved social medicine
from developing into a movement for sanitary reform.
Grotjahn
•Codified basic principles of Social Pathology
•The significance of a disease from a social point of view is determined
in the first place by the frequency with which it occurs.
• Medical statistics are therefore the basis for any investigation of social
pathology.
•The most important relations between the diseases and the social
conditions are naturally in the realm of causation.
07/01/2025 20

•The etiology of disease is biological and social. So far only the
biological etiology has been studied extensively.
•Social conditions (a) may create or favour a predisposition for a
disease, (b) may themselves cause disease directly, (c) may
transmit the causes of disease, and (d) may influence the course of
a disease.
07/01/2025 21

Friedrich Engels
•The Condition of the Working Class in England ([1844] 1973 ), which
provided valuable insights into disease causation among the English
working class.
•Engels traced diseases such as tuberculosis, typhoid and typhus to
malnutrition, inadequate housing, contaminated water supplies and
overcrowding.
•Engels’ epidemiologic investigation of mortality rates and social classes
using demographic statistics compiled by public health officials is an
excellent example of his holistic vision.
• He showed that mortality rates were inversely related to social class,
not only for entire cities but also within a specific geographic district of
a city.
07/01/2025 22

Friedrich Engels
•He noted that in Manchester, childhood mortality was much greater
among working- class children than among ‘children of higher class.
•In addition, he commented on the cumulative effects of deprivation and
urbanization on childhood mortality.
•He gave data that demonstrated higher death rates among working-
class children from epidemics of infectious diseases like smallpox,
measles, scarlet fever and whooping cough.
07/01/2025 23

Villermé of France
•Analysed the differential mortality rates in different Paris
arrondissements (city districts).
•Villermé analysed the economic status of the inhabitants, using rent
levels identifiable through tax liabilities, as an indicator of wealth.
•The result was that untaxed tenants, who represented the poorest
inhabitants, consistenty showed the highest levels of mortality within
arrondissements.
07/01/2025 24

07/01/2025 25
Villermé of France
The great significance of Villermé, Snow:
•Focused on identifing those factors in the environment that are
important to disease aetiology.
•Establish the value of the population perspective to the study of
disease and forged strong links between epidemiology and public
health.
•The idea that epidemiology is the basic science of public health,
thus, clearly has its origin in the works of the early nineteenth-
century epidemiologists.
•Epidemiology contributes to the rationale of public health policies
and services and is an important tool in their evaluation.

SHIFTING
PARADIGMS OF
MODERN
EPIDEMIOLOGY
•The core idea that epidemiology is the basic
science of public health, which brings the
population perspective to the study of health and
disease, is now in question.
•The new formulations are rooted in a positivist
conception of epidemiology, with strong roots in
the capitalist mode of production.
• The three pathways traversed by modern
epidemiology, namely, risk factor, clinical
epidemiology and molecular epidemiology,
clearly indicate that they are united by a
common theoretical framework reliant on a set
of narrow, individualist, clinical and
biological perspectives on health and disease.
07/01/2025 26

RISK FACTOR
EPIDEMIOLOGY
•Risk factor epidemiology entails the use of
methods and techniques of epidemiology to
identify factors that have protracted effects
on health.
•Individuals are studied in terms of their
eating, drinking, smoking and exercise
habits, to ascertain whether these increase or
decrease risk.
•Similarly, individuals’ weight and height,
medical history and physiological status are
studied.
07/01/2025 27

•Discovery of the germ theory of disease which emphasised the role of
biological agents and microorganisms in disease causation.
• In the 1880s, the German bacteriologist Robert Koch proposed a
set of requirements to guide researchers in making causal inferences.
•Koch’s approach demanded that investigative work be carried out in
the laboratory, with the investigator isolating the causative agent and
studying its presence under the microscope for each case of disease.
•Thus, Henle, Snow, Pasteur and Koch can be considered as the
symbolic founding fathers of the shift in the paradigm of
epidemiology.
07/01/2025 28

•The new paradigm of disease that followed from their work – germ
theory – led to the emergence of a narrow laboratory perspective of a
specific cause model relating single agents, one to one, to specific
diseases.
•The focus of epidemiology was restricted to the pursuit of specific
agents, singular causes and the means of preventing their
consequences.
•The concept of risk factor is based on individual risk; individual
behaviour, or the individual himself, is perceived to contain the
problem. This approach therefore atomises both causations and
solutions, because the basic causal reasoning implies that
interventionist strategies will be directed towards individuals.
07/01/2025 29

•Risk factor has provided space for the medicalisation of society
and has become the founding stone of the lifestyle approach to
disease prevention and control.
•The objective of risk factor epidemiology is to promote awareness
of the potential dangers unleashed by individual lifestyle choices
and, then, to motivate the individual to participate in health
promotion and health education programmes.
•The fundamental weakness of this approach is that it is based on a
very narrow definition of risk, emphasizing only one aspect of risk,
that is, individual risk.
07/01/2025 30

•The study of suicide, for instance, exposes many of the limitations of
the risk factor approach. ‘Without the formulation of an alternative
research strategy, the epidemiological investigation of suicide amounts
to further refinement of components such as methods of determining
historical trends, characteristics of populations at risk, and
variables associated with the waxing and waning of rates’.
•Risk factor epidemiology, in effect, reduces epidemiology to the role
of identifying, measuring, ranking and predicting risk factors relating
to individual behaviour, totally disregarding the potential contribution
of epidemiology based on a population perspective.
07/01/2025 31

CLINICAL
EPIDEMIOLOGY
•Two parent disciplines: clinical medicine and
epidemiology
•It is ‘clinical’ because it seeks to answer
clinical questions and to guide clinical
decision making with the best available
evidence.
•It is ‘epidemiologic’ because many of the
methods used to answer these questions have
been developed by epidemiologists and
because the care of individual patients is seen
in the context of the larger population of
which the patient is a member.
•Clinical epidemiology as an independent
discipline, in its modern form, emerged only
in the early 1980s.
07/01/2025 32

•John R. Paul founded clinical epidemiology. It is a science concerned
with circumstances, whether they are ‘functional’ or ‘organic’ model
which human disease is prone to develop.
•It would be based on ‘a marriage between the quantitative concepts
used by the epidemiologists to study disease in populations and
decision- making in the individual case which is the daily fare of
clinical medicine’.
07/01/2025 33

•Notions of causation are compressed and limited to the boundaries of
the individual realm, where disease is treated in isolation from social
reality.
• Anything that cannot be shown to interact with the organism to
produce a morbid state is increasingly excluded.
•Thus, clinical epidemiology brings to focus only the most immediate
and the local and prescribes a solution that is based solely on the
elimination of symptoms and restoration of normal signs.
•Foucault contrasts this medical thought with epidemiological tradition
and perception, which sees the problem of disease as a ‘nucleus of
circumstances’, ‘a complex set of interactions’, in which the only
individuality is a ‘historical individuality’.
07/01/2025 34

•The detailed study of aetiology in clinical epidemiology is confined
to the investigation of individual cases or cases of rare diseases.
•The answer to the problem of ill health is then, logically, expected to
be found in the same professionalised and individualised treatment,
not in a reordering of the social, political and environmental world.
07/01/2025 35

•In the case of smoking, these preconditions include a powerful
cigarette industry; social and cultural forces, including norms that
sanction smoking; social and economic forces that induce stress and
thus tobacco addiction; and projection of an identity or image by all
forms of media, advertising, literature, movies, folklores, etc.
•The idea that the smoker is free to smoke or not smoke is actually a
false notion of individual freedom.
•Ignoring the sociocultural environment in which the individual makes
his/her choice, the conclusion drawn is that the individual voluntarily
‘chooses’ to smoke; thus, the responsibility of the ill health resulting
from his/her so-called voluntary action also falls on the individual
himself/herself.
07/01/2025 36

•J.M. Last notes that neglect of the population perspective and
medicalisation of the concept of epidemiology will have adverse
consequences for public health because ‘medical graduates may not
know how to assess the health problems of the communities in
which their practices are located, and what is worse, they may not
care’.
•He further notes: ‘clinical epidemiology is an inappropriate,
pretentious, and internally inconsistent term to apply because
epidemiology refers to populations, and “clinical epidemiology”
often refers to individual persons.
•In the clinical epidemiology approach, Physicians hardly bother
about the two vital aspects of public health policy, namely, disease
prevention and health promotion.
07/01/2025 37

MOLECULAR
EPIDEMIOLOGY
•Molecular epidemiological development
depends on development within the field
of molecular biology, which studies
organisms at the subcellular level.
•It emerged as a recognised, independent
sub-discipline of epidemiology in the
1980s in three separate, substantive areas,
namely, cancer epidemiology,
environmental epidemiology and
infectious disease epidemiology.
•Bernard Weinstein (1982) first
popularised the term ‘molecular
epidemiology’ in the early 1980s to
describe aspects of their ongoing research
on cancer aetiology.
07/01/2025 38

•Molecular biology, considered the backbone of molecular
epidemiology.
•Molecular biologists claim that virtually all diseases have a
genetic component, at least to a certain degree.
•William A. Haseltine (Chairman, Human Genome Sciences, a
biotech firm based in Maryland, United States) claims that ‘the
medical paradigm is changing’.
•Medicine is going to change from a treatment-based to a
prevention-based discipline.
07/01/2025 39

•The Human Genome Project set for itself a challenging objective:
to gain complete knowledge of the organisation, structure and
function of the human genome, the master blueprint for us all
(Department of Energy 1992 ).
• The project has been successful in mapping the genome and
identifying all its estimated 75,000–100,000 genes.
•With the help of this, scientists hope to locate a disease gene
which determines the complete sequence of the genetic code of
disease.
•They can devise a test for the presence of that gene in any patient.
07/01/2025 40

•Weinstein admits that one of the reasons why he chose to conduct
research along the lines of molecular epidemiology was the glamour
associated with molecular biology.
• However, the main reason was the ‘possibility of developing a number
of biochemical and molecular tools that epidemiologist could use to
better define the etiology of specific human cancers’.
•Some epidemiologists now believe that molecular epidemiology is the
best pathway for the future of the discipline of epidemiology.
•Molecular techniques are directed principally at enhancing the
measurement of exposure, effect and susceptibility, and not at
formulating new hypothesis (about aetiology).
07/01/2025 41

•The glaring error of this approach is that in its search for the Holy
Grail (Hall 1989), molecular biologists have chosen to
overemphasise the role of the gene to the exclusion of almost all
other factors.
•‘The language of biomedicine and illness in genetic stories clearly
extends the Cartesian tradition of reductionism and dualism …
objectifying the body and making the genome rather than the
person, the focus of medical attention’.
•Such biological determinism clearly excludes social and
environmental factors from the causal model.
• The gene focus draws attention away from critical questions about
why this person is ill in this place, at this time and how changes in
his/her situation might erase the problem.
07/01/2025 42

CONCLUSION
•The period from the late eighteenth to the early
twentieth century was characterised by the most
intense and wide use of epidemiology in public
health.
•The population perspective gained prominence
in the theorisation, empirical findings and policy
applications of the anticontagionists.
•The process of individuation, biologism and
reductionism started with germ theory.
•Through the shifts in epidemiology, the
population dimension was reduced first to the
individual dimension and finally to the
molecular dimension.
07/01/2025 43

CONCLUSION
•This effectively obviated the dynamics of
interaction between the individual and his/her
environment with its consequent impact on
health and promoted ‘victim blaming’.
•Behavior modification, clinical medicine and
genetic decoding of disease, all of which
became the guiding principles of public health.
•These do not admit of social and economic
influences on choice of occupation, lifestyle,
sanitary conditions and a range of other factors
that affect health, and which remain outside the
control of the individual.
07/01/2025 44

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