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ISDC 2002 - Palermo, Italy
Communities with Multiple A fflictions:
A System Dynamics A pproach
to the Study and Prevention
of Syndemics
Jack Homer
Homer Consulting
Voorhees, New Jersey, USA
Bobby Milstein
Centers for Disease Control and Prevention (CDC)
Atlanta, Georgia, USA
Abstract
The term syndemic was coined by the medical anthropologist Merrill
Singer to describe the mutually reinforcing nature of health-related problems such
as substance abuse, violence, and AIDS, that disproportionately impact inner city
neighborhoods burdened by economic hardship, deteriorated infrastructure, social
disruption, malnutrition, and inadequate health care.
Public health scholars agree that effective responses to the intertwined
afflictions within communities throughout the world require comprehensive,
system-wide interventions. To strengthen the scientific foundation for such
initiatives, the CDC is supporting research on syndemics, including the use of
system dynamics modeling to investigate how and why syndemics develop, and to
evaluate alternative approaches to intervention for particular community contexts.
At present, a generic (not yet case-specific) model has been developed
based on the literature and expert observations. This preliminary model is available
as a web-based game at: http://broadcast.forio.com/sims/syndemic. We present the
model and some results, and outline plans for carrying the work forward.
A Syndemic is...
The spread and persistence of mutually reinforcing
health-related problems such as substance abuse,
violence, and AIDS, typically found in inner city
neighborhoods burdened by economic hardship,
deteriorated infrastructure, social disruption,
malnutrition, and inadequate health care.
Singer M. 1994. AIDS and the health crisis of the US urban poor: The perspective
of critical medical anthropology. Social Science and Medicine 39(7): 931-948.
Singer M. 1996. A dose of drugs, a touch of violence, a case of AIDS:
Conceptualizing the SAVA syndemic. Free Inquiry in Creative Sociology 24(2):
99-110.
A Web of A fflictions
Public Health Goals
¢ Preventing disease and injury
¢ Prolonging life
¢ Reducing overall burden of illness
¢ Avoiding activity limitation
¢ Maintaining emotional balance
¢ Eliminating health disparities
¢ Enhancing life satisfaction
Standard Practice Falls Short
¢ Public health scholars agree: Effective responses
to the health problems of the urban poor and other
communities require system-wide interventions.
¢ However, most public health agencies continue to
act as if each affliction can be prevented
individually by understanding its unique causes
and developing narrowly targeted interventions.
¢ This compartmentalized approach is engrained in
the agencies’ financial structures, scientific
frameworks, and statistical models.
A
A Change in Perspective
syndemic public health orientation:
Places multiple afflictions in context, and
identifies systematic links among them
Assesses the influence of community conditions
Assesses the capacity of community organizations
to direct health and social policy change
Brings together the sciences of epidemiology and
system dynamics with the action agenda of
community leaders
Core Public Health Functions
Under a Syndemic Orientation
ASSESSMENT
Social ( ] Network
Navigation Analysis
Syndemic
cata)
ASSURANCE Dynamics DEVELOPMENT
Model Overview
Affliction-related death
Outside assistance
7 to fight affliction
a.
Out-migration of Affliction Community efforts
nor-afflicted prevalence |. ~__o fight affliction Outside assistance
“J Pa build capacity
o/\e
Affliction contagion \ Community
and cross-impacts community <é&—— capacity
@) capacity
em ivesinents in ®)
General community
community Disruption due to
conditions outside assistance
> @)
Community efforts
to improve general 7 ;
conditions Outside assistance to
improve general
conditions
Population Stocks & Flows:
3 Affliction Types (A, B, C)
" 8
Death AO Death ABO
Net flow AO to ABO
it aa
SSS
Popn AQ i) Pop) ADD << —————
Net flow 0 to AO Net flow BO to ABO r Net flow ABO to ABC
Y Net flow 0 to BO Y et flow BO to BCO NetflowBCO to
OY] popn Popn BO lag Popn BCO Ae
Births ~ nonafflicted’ <== | p > Pop $$ Popn ABC =
& ‘arati Death ABC
Net outmigration
A Death BO A ' Death BCO A
Death 0 t Net flow CO to BCO
—————— Popnco Popn ACO
=> Net flow ACO to
ABC
NEpriow’)'te 0 Net flow AO to ACO
Death CO { f i Death ACO
Net flow CO to ACO
Incidence & Recovery Logic
Noncontagious Contagion rate B
incidence rate B
. Effect of having A
Fraction of popn incidence rate B on incidence B
at risk for B from 0
Incidence rate B
<Community effort from AO
aoe against B> <P revalence of B>
conditions>
Incidence B
from AO
atid Popn Ad Popn ABO
revalence B
B Net flow AO to ABO
Recovery rate B
Pon Bo Recovery B
from ABO Effect of having A
on recovery B
Recovery rate B
from ABO
Websim Introductory Screen
http://broadcast.forio.com/sims/syndemic/
Three mutually compounding afflictions—let’s call them A, B, and C—have just
been introduced to a community. The general community conditions are only
mediocre and not supportive of healthy living, so the threat of a growing
"syndemic" is quite real. Your goal is to minimize the community’s burden of
affliction over a twenty year period.
The community is already making an effort to improve general conditions, but
its internal capacity to do so is limited, and more could be done with backing
from government and philanthropies. Government agencies and foundations
could also step in with programs to help fight the afflictions directly by
developing policies and services that reduce rates of incidence and boost rates
of recovery. A third type of assistance would be leadership training and
organizational development to build up the community's internal capacity for
action of all sorts.
The government and philanthropic organizations have sufficient resources to
fund all three types of assistance, but only for a limited number of years. You
must decide (1) when to initiate each type of assistance, (2) how widely the
community will be involved in externally-funded programs, and (3) how heavily
each of the affliction types will be weighted in the community's allocation of
effort.
A Severe Syndemic
Base conditions=.50, No outside assistance
12,000 people
1 index
6,000 people
0.5 index
ee
0 people
0 index
0 2 4 6 8 10 »=«12 1416 18 = 20
Y ears elapsed since first incidence of afflictions
Popn total : Base50 people
Popn afflicted : Base50 people
Community effort against affliction : Base50 index
General community conditions : Base50 index
Community capacity : Base50 index
A Milder Syndemic
Base conditions=.70, No outside assistance
12,000 people
1 index
6,000 people
0.5 index
0 people
0 index
Popn total : Base70
Popn afflicted : Base70
Community effort against affliction : Base70
General community conditions : Base70
Community capacity : Base70
_L—<——
0 2 4 6 8 10 12 14 ~ «16
Y ears elapsed since first incidence of afflictions
people
people
index
index
index
Focusing on a Single A ffliction
All weight on fighting A, No outside assistance
0.8
0.6
0.4
0.2
0 2 4 6 8 10 12 14 16 18 20
Y ears elapsed since first incidence of afflictions
Affliction prevalence : AllWeightA fraction
Affliction prevalence : Base50 fraction
A prevalence : AllWeightA fraction
A prevalence : Base50 fraction
Outside Assistance - A ffliction
Assistance to fight affliction for 10 years
0.8 fraction
1 index
0.4 fraction
0.5 index
0 fraction
0 index
0 2 4 6 8 10 12 14 16 18 20
Y ears elapsed since first incidence of afflictions
Affliction prevalence : AssistF10 fraction
Affliction prevalence : Base50 fraction
Community effort against affliction : AssistF10 index
Community effort against affliction : Base50 index
Community capacity : AssistF10 index
Community capacity : Base50 index
Outside Assistance - Capacity
Assistance to build capacity for 10 years
0.8 fraction
1 index
0.4 fraction
0.5 index
fraction
index
oo
0 2 4 6 8 10 12 14 #16 18 = 20
Y ears elapsed since first incidence of afflictions
Affliction prevalence : AssistC10 fraction
Affliction prevalence : Base50 fraction
Community effort against affliction : AssistC10 index
Community effort against affliction : Base50 index
Community capacity : AssistC10 index
Community capacity : Base50
Outside Assistance - Conditions
Assistance to improve general conditions for 10 years
0.8 fraction
1 index
0.4 fraction
0.5 index
oo
0 2 4 6 8 10 12 14 16 18 20
Y ears elapsed since first incidence of afflictions
Affliction prevalence : AssistGI1 fraction
Affliction prevalence : Base50 fraction
Community effort against affliction : AssistGI1 index
Community effort against affliction : Base50 index
Community capacity : AssistGI1 index
Community capacity : Base50 index
Outside Assistance - Combined
Combined (non-disruptive) assistance for 10 years
0.8 fraction
1 index
0.4. fraction i
0.5 index
0 fraction
0 index
0 2 4 6 8 10 12 14 16 18 = 20
Y ears elapsed since first incidence of afflictions
Affliction prevalence : AssistCGFI1
fraction
Affliction prevalence : Base50 fraction
Community effort against affliction : AssistCGFI1 index
Community effort against affliction : Base50 index
Community capacity : AssistCGFI1 index
Community capacity : Base50
index
I
WE
aa
Syndemics
Prevention Network
htto://www.cdc.gov/syndemics
Web-based simulator & model background:
http://broadcast.forio.com/sims/syndemic/
Syndemics Prevention Network:
U.S. Members 2001-2
a4 ee International
1 6 * Argentina
rp) * Australia
_— * Canada
* Grenada
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