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Vineis paolo la malattia come sistema complesso-torino gennaio 2011-14° convegno patologia immune e mal
1. La malattia come sistema complesso: normale,
patologico e concetto di causa
Paolo Vineis
Imperial College London e HuGeF Foundation Torino
Torino, 21 gennaio 2011
2. Sharp boundaries ?
When we adopt a classification of disease (e.g.
ICD-10), or when we refer to the diagnostic
criteria for disease, or when we think of causes, we
usually imply that such activities are based on
unequivocal criteria that sharply distinguish a
disease from another one, or that relate a cause to
its effect. This is very clear in the paradigm of
“necessary and sufficient” causes.
3. Although it is admitted that in special
circumstances a “fuzzy” interpretation is needed,
the idea of “fuzzy sets” has not been generalized.
However, fuzzy sets are the rule, not the exception
(Bowker and Star: Sorting things out).
This applies to disease classification, diagnosis and
causal interpretation.
4. Fuzziness, i.e. lack of sharp boundaries,
corresponds to the fact that different objects
(belonging to the same category) do not have a single
characteristic in common (i.e. a necessary and
sufficient characteristic).
This corresponds to Wittgenstein’s idea of “family
resemblances”
5. To say that language is used in a fuzzy way and that
there are degrees of truth does not mean that truth
does not exist or cannot be found.
Not everything is a matter of opinion, or relies on
interpretation. Simply, truth comes in degrees
and has a continuous distribution between 0 and 1
(“membership function”).
6.
7. Darwin: “I look at the term species as one arbitrarily given, for
the sake of convenience, to a set of inividuals closely resembling
each other”.
sparrow ABC
crow BCD
eagle CDE
ostrich DEF
penguin EFG
What is now defined “species” is a cluster of individuals who
have a common ancestor and have adapted to a common
ecological niche.
18. Charles Darwin
Evolution by natural selection
The theory of evolution by natural selection based on the
analysis of functional causes involving final causes where
the existence of God is not taken into account.
Darwin hypothesizes that during evolution, the variation of
organisms is caused by random mutations filtered by the
action of natural selection (adaptation is the ‘goal’).
Epigenetics – Philosophical insight
19.
20. Evolutionary medicine tries to explain health
and diseases according to the theory of
evolution.
According to “neo-darwinism” the
appearance of new species is related to
mutations and selection of the fittest (where
fit means adapted to a specific environment)
There are both scientific and epistemological
controversies
21. This paradigm has many potential
applications. For example in medicine:
- resistance to antibiotics because of
selection of bacteria with survival advantage
- resistance of cancer cells to
chemotherapies
A book to read: M Greaves: Cancer, the
evolutionary legacy. OUP, 2001
25. Darwin after Mivart’s objection
‘In
‘In my opinion, the greatest error which I have
committed, has not been allowing sufficient
weight to the direct action of the environment, i.e.
food, climate, etc., independently of natural
selection’
Charles Darwin to Moritz Wagner, 1876
26. Concept of “norm of reaction” and phenotypic
plasticity (Waddington)
27.
28. Odds ratio for impaired glucose tolerance or type 2 diabetes according to birth weight
among 370 men aged 64 years born in Hertfordshire (adjusted for adult body mass index).
Hales C N , Barker D J P Br Med Bull 2001;60:5-20
29. Odds ratio for the metabolic syndrome according to birth weight among 407 men born
in Hertfordshire (adjusted for adult body mass index).
Hales C N , Barker D J P Br Med Bull 2001;60:5-20
30. The original diagrammatic representation of the thrifty phenotype hypothesis.
Hales C N , Barker D J P Br Med Bull 2001;60:5-20
36. Reduction in absolute risk
Benefit
Threshold
Harm
Baseline risk of adverse outcome
et al.
BMJ 1995
Glasziou P,
37. The whole issue of “end of life” is confused by the fact that
most people look for crisp boundaries where there is a
continuum.
Irreversible loss of conscience
Total brain death
Cardiac arrest
belong in a continuum, though they have completely different
practical implications.
An interesting point of view is represented by the Danish
Etiske Rad, that acknowledges the continuous nature of the
death process (up to a point), i.e. dying lasts in time. Brain
death is an irreversible process that leads to the whole body’s
death. It is not a state.
