Causes of disease, bio-social mechanism

1. On the causes of disease
Or, what a bio-social mechanism is*
Federica Russo
Philosophy | Humanities | Amsterdam
russofederica.wordpress.com | @federicarusso
* Based on joint work with M. Kelly and R. Kelly

2. Overview
Disease mechanisms: recent debates
Biological causes, the proximal-distal distinction,
and current views on social causes
When the social was proximal
Rehabilitate older, holistic views of health and disease
Lifeworlds and mixed mechanisms
How the social enters disease aetiology
Examples
Integrated explanations of disease, public health interventions, campaigns
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3. MODELS OF PATHOGENESIS
In the aftermath of the germ theory of disease
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4. Biological causes of disease
The conceptualisation of disease
The outcome of exposure to a pathogen or other noxious factor
Pathogens are causal factors
They trigger mechanisms that lead to disease
Biologisation of disease
A heir of the germ theory of disease and of the isolation of
bacteria
A consequence of the experimental turn in medicine
Complications
Multiple pathogens at work, etc.
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5. The proximal – distal distinction
The role of social epidemiology
Biological causes are proximal, social causes are distal
Distal causes do not exert direct influence on health
Hence, social causes are at best classificatory devices,
but not active causes in disease aetiology
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6. Social causes of disease?
A number of accounts try to bring in social causes
Engel; Susser & Susser; Rose; Marmot & Wilkinson;
Thisted; Cockerman; Galea; …
Either the social is used to classify disease,
or it is not integrated in disease mechanisms
Krieger’s web of causation
Gets quite close to the idea of integration
But social factors are not explanatory
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Biopsychosocial model:
more about medical
practice than disease
causation
Chinese boxes: more
about levels of
organisation than
integration
Population strategy:
social and biological on
par, but no explanation
of integration
Social determinants of
health inequalities, not
focus on disease
aetiology

7. WHEN THE SOCIAL WAS PROXIMAL
Moving forward is moving back to the origins
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8. The original public health vision
Public health interventions targeted social factors
John Snow
Rudolf Carl Virchow
William Duncan
William Tennant Gairdner
…
Social inequalities > health inequalities
Explanation of and action on health inequalities
integrates the social and the biological
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Stops the cholera
epidemics in London
by acting on a social
mechanism
Medicine is a social
science, social
inequalities cause
disease
The social is the root
cause of diseases,
interventions targeted
living conditions

9. THE ARGUMENT
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10. Against the proximal – distal distinction
For an integrated aetiology of disease
Integration means explaining disease with mixed
mechanisms
Public health intervention or individual treatment
may target social and/or biological factors
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11. LIFEWORLDS AND
MIXED MECHANISMS
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12. The social world. And health.
Sociology attempts to explain and predict
human behaviour
Societies manifest observable patterns of change
Humans are thinking and acting beings
Their thought and action take place within the
constraints imposed by social structures
How is behaviour linked to health?
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13. Initiates and mediates
exposure to toxins,
hazards, pathogens, etc
Drives health states of
individuals and
populations
Is the product of the
interaction between
human agency and
social structure
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14. An integrated pathogenic approach
The ‘social’ and the ‘biological’ are integrated in the
aetiology of disease
Behavioural factors are active parts of disease
mechanisms
Disease mechanisms are mixed
Social and biological factors are on a par
Social factors are not mere classificatory devices
The social and the biological together explain
disease
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15. EPIGENETICS
Integrated explanation of disease
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16. The epigenome reflects
acquired and inherited
genetic modifications
Recent studies show how
socio-environmental
pressures are linked to
epigenetic changes in the
short term
One generation distance
Pregnancy
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Epigenetic changes due to
social and environmental
pressures
Disease
Environm
ent
Behaviou
ral factors
Epigenetic
changes

17. DISEASES CAUSED BY
ALCOHOL CONSUMPTION
Integrated explanation of disease
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18. Alcohol consumption is part of
the lifeworld of individual and
of groups
It varies across friends, family,
social groups, populations,
age groups, etc
Just reducing exposure to the
‘pathogen’ does not reduce the
burden of disease
Broader interventions on
lifeworlds are needed
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Alcohol-related diseases are
not caused just by alcohol
consumption
Disease
Environm
ent
Behaviou
ral factors
Biological
factors

19. OBESITY: CAUSES, MECHANISMS,
INTERVENTIONS
A public health action

20. Biological hypotheses
Genetic factors, insuline regulation, …
Socio-economic-psychological hypotheses
Family habits, peers imitation, …
MEND : « Mind, Exercise, Nutrition, … Do It! »
Interventions
Target: individual, groups, family of obese children …
Biological and psychological factors, education, …
http://www.mendcentral.org/

21. THE GIRL EFFECT
A campaign
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22. Young girls, poverty, pregnancy, and HIV
A global movement and collaboration between
foundations, health departments, …
http://www.girleffect.org
A video
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23. TO SUM UP AND CONCLUDE
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24. Health and disease are complex phenomena
Biological and social aspects studied in detailed
However …
Biological and social components of disease
Different roles
Proximal – distal
Classificatory – explanatory
An integrated aetiology of disease
Puts biological and social factors on a par
Points to a concept of ‘mixed mechanism’ where both are
‘active’ causes to explain disease
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