Transcript Explorations in regime change: b

Explorations in regime change:
b-Thalassaemia and the interplay of
technological change & social norms.
Zosia Bornik & Hadi Dowlatabadi
University of British Columbia
with thanks to:
Sue Cox, Peter Danielson, Ed Levy and Bernadette Modell
Overview
•
•
•
•
•
Objective of this research
Definitional issues.
Domain information.
Findings.
Conclusions/more
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Objective
• At UBC:
– Study democratic issues related to applied
genomics.
• At CMU:
– To explore features of regime change.
• Synthesis:
– What might drive shifts in social norms?
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Social Norms
• As a noun:
– It describes how a peer group shares specific values and
hence chooses among a set of options.
• As a verb:
– It is used as an approach to risk communication and
intervention. It has been successfully employed to
address excessive drinking among college students…
• Recent History:
– Based on research by Alan Berkowitz and H. Wesley
Perkins working at Hobart and William Smith Colleges.
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A two-level model of behaviour
• Norm based heuristics:
– “There are the values we hold”
• Deliberated decision:
– “I know what is valued and estimate the
benefits of this to outweigh its costs …”
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The question:
• What makes the higher level of decisionmaking be revised?
• Changing circumstance:
–
–
–
–
Social
Economic
Technologic
…
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An example:
Thalassaemia
• Thalassaemia, is an inherited condition where the
genes controlling haemoglobin production are
affected.
• Each hemoglobin molecule contains four subunit
proteins (2xa and 2xb).
– Hemoglobin properly binds and releases oxygen only when
two alpha subunits are connected to two beta subunits.
– A pair of genes located on chromosome #16 controls the
production of the alpha subunits of hemoglobin.
– A single gene located on chromosome #11 controls the
production of the hemoglobin beta subunit.
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Its in the genes
b-globin genes
a-globin genes
a1
b1
b2
a3
a2
a4
Hemoglobin
Protein
Chromosome 11
Chromosome 16
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b-Thalassaemia
• When the b-globulin genes (or their neighbours)
are defective or absent, the patient suffers from
b-Thalassaemia of different severities.
– Minor: where haemoglobin production is slightly affected
– Intermedia: …
– Major: where both genes are affected leading to severe
anaemia.
• Patients with b-Thalassaemia major need:
– chronic blood transfusions
• AND
– Chelation therapy (to address iron over-load)
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Clinical intervention
1.
2.
3.
4.
Diagnose anaemia
Test for b-trait using haemoglobin electrophoresis
Blood transfusions
Iron-Chelation therapy
• ≥2 units of blood/mo.
• Liver, heart & other medical problems
• ≥15 days/mo. of Chelation therapy
•
Source: Zeuner et al, 1999
Life expectancy: ~ 60yrs
• Cost: CDN$1-2 M
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Social intervention
1. Identify potential carriers
2. Give them genetic counselling
3. Bring pressure to avoid pregnancy
•
Source: Zeuner et al, 1999
Revised norms on procreation
• Cost: CDN$ 6-100/cap
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Genomic interventions
1.
Test the genes:
•
1.
Pre-natal
Test the genes:
•
Pre-implantation
2.
3.
Give genetic counselling
Offer termination of
pregnancy
2. Give genetic counselling
3. Try in-vitro fertilization
again
•
•
Revised norms on abortion
Cost: CDN$ 150-1000/test
•
•
Sources: Verma 2003, Karczeksi 2003
Revised norms on eugenics
Cost: CDN$ 4000-5000/test
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The Thalassaemia Belt
•
2-18% of the population consists of carriers (WHO, 1994)
•
Population movements have led to dissemination of the gene…
– includes Mediterranean Region, Middle East, Indian Subcontinent, and
Far East
– ß-Thal now widespread in Europe, Americas and Australia. In 2002:
– ~ 240 million healthy carriers worldwide.
– ~ 200,000 ß-Thal major births per year (Cao et al, 2002).
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Fall in Thalassaemia Major with
screening
Source: Modell
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The choices made in Cyprus
• 4% chose a different marriage partner.
• 20% chose a smaller final family size.
• 76% had selective abortion.
Source: Modell
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Fall in Thalassaemia Major Births
Source: Modell
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Uptake of pre-natal diagnosis by ethnic
group (UK)
100%
1st Trimester
2nd Trimester
80%
60%
40%
20%
0%
Cypriot
Source: Modell
Indian
Pakistani
Other
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Technological
Change
Diagnosis
Improve
infants
survival
Transfusio
n
services
Improve
child
survival
Desferrioxamine
Control
health
spending
Social
Change
Revise
social
norms
High infant
mortality
Typically
150/1000
Genetic
screening
Some get blood
transfusions
IM drops to ~
40/1000 of which
17% are ß-Thal
major!
Some get Iron
Chelation
therapy
Most are not
born
IM drops by
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another ~7/1000
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Why was Cyprus so successful?
Cyprus:
• Genetically homogeneous
population 2-3 mutations.
• High prevalence rate 14%
carrier rate.
• Broad public engagement
through church, schools
and community.
Elsewhere:
• Genetically heterogeneous
(e.g., >23 mutations in Iran).
• Lower prevalence rate (and
priority).
• Dominated by other
concerns/norms.
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Conclusions
• When pressure is sufficiently high norms
can shift (i.e., Cyprus, Italy, Iran).
– Perhaps such shifts are more readily accepted
because they also address other objectives.
• Pressure to “preserve norms” (itself a norm
at a higher level) trumps where population
is heterogeneous(i.e., UK).
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Clinical Intervention costs
from Zeuner et al, 1999
Average life expectancy = 63 years
Total lifetime treatment costs for B-thal major = 490,000 British pounds
= 123,000 at a 6% discount rate
(includes diagnosis, blood transfusion, outpatient visits, costs assoc w/ complications)
For costs incurred over different life stages, see Table 33, p.68
Social Intervention costs
from Zeuner et al, 1999
Total antenatal screening programme costs per 10,000 population group
= 33,869 – 800,060 British pounds
(see CB analysis and Table 55, p. 90)
(includes carrier screening, counseling, pre-natal Diagnosis, and abortion)
Genomic Intervention costs
Cost for Pre-natal Diagnosis depends on country
India = 150$ Canadian per case (Verma, 2003)
USA = 1000$ Canadian per case (Karczeksi, 2003)
Predicted costs for Pre-implantation Genetic Diagnosis
USA = at least 4000-5000$ Canadian per case (Karczeksi, 2003)
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