Using GIS to investigate multiple deprivation David Briggs Small Area Health Statistics Unit...
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Transcript of Using GIS to investigate multiple deprivation David Briggs Small Area Health Statistics Unit...
Using GIS to investigate
multiple deprivation
David Briggs
Small Area Health Statistics Unit
Imperial College, London
A few thoughts and several questions
SAHSU and Environmental Injustice
• Socio-economic deprivation shows (often strong) associations with health outcome and exposure in most SAHSU studies
• Studies designed to minimise potential confounding by deprivation (small-area, case-crossover etc)
• Control is typically by using a (group-level) measure of socio-economic deprivation (Carstairs) in the logistic regression analysis
But….
• Do we over-control?
• Is deprivation really a confounder or effect-modifier?
• What is it about deprivation that affects health – and how should it be measured?
Question 1. Why are we interested in Environmental
Injustice
• Good science
• Good policy
• Moral justice
• Trendy subject
Landfill site density and population
density, UK Nr of landfill sites per 5 x 5 km21
2
3 - 4
5 - 8
9 - 68
0.00
1.00
2.00
3.00
4.00
5.00
6.00
0 - 9 10 - 19 20 - 29 30 - 39 40 - 49 50 - 59 60 - 69 70 - 79 80 - 89 90 - 100
Percentage Urban
Rat
e ra
tio
: ex
po
sed
/un
exp
ose
d
0
50
100
150
200
250
300
350
1 2 3 N/A
Nu
mb
er
of
po
stc
od
es
(th
ou
sa
nd
s)
< 2km
> 2km
Not known
Affluent Deprived
Proximity to landfill sites by
socioeconomic status and urban
area
0
20
40
60
80
100
0.00-0.10 >0.10-0.48 >0.48-1.00 >1.00-4.80 >4.79-10.0 >10.00
Distance from powerlines
Pe
rce
nta
ge
Affluent 2 3 4 Deprived
`
Socio-economic status by
distance from powerlines (km)
Odds ratios of living within 100 metres of a powerline, by
socio-economic status
0.6
0.8
1
1.2
1.4
1.6
1 2 3 4 5
Carstairs quintile
Od
ds
ra
tio
Affluent Deprived
1966-69
Black Smoke
Car
stai
rs
50 100 150 200 250
-50
510
15
1970-73
Black Smoke
Car
stai
rs
0 50 100 150 200
-50
510
15
1974-77
Black Smoke
Car
stai
rs
0 20 40 60 80 100 120
-50
510
15
1978-81
Black Smoke
Car
stai
rs
0 20 40 60 80
-50
510
15
1982-85
Black Smoke
Car
stai
rs
0 20 40 60
05
1015
1986-89
Black Smoke
Car
stai
rs
10 20 30 40 50 60
05
1015
1990-93
Black Smoke
Car
stai
rs
5 10 15 20 25 30 35
05
1015
Exposure to black smoke and deprivation for different time
periods, urban wards UK
Socio-economic deprivation and environment
Exposure Direction Comment
Traffic-related air pollution + Strong
Industrial air pollution + Strong
Road traffic noise + Strong
Aircraft noise +/ Varies by country
Disinfection byproducts +/ Varies by region
Landfill sites + Urban/industrial
Radon Rural/upland
Powerlines/EMF +/ Varies urban/rural
Mobile phone masts +/ Varies urban/rural
Question 2
How do these associations develop?
• Imposed (via planning process) – e.g. major point emitters?
• Evolved (as population changes in response) – e.g. roads, airports?
• Geographic coincidence (i.e. shared, but independent, geography of hazard and SES) – e.g. radon, powerlines?
• Historical legacy (i.e. inherited from past) – e.g. landfill sites
Health Period 1: 1981-84
Carstairs
Rela
tive R
isk
-5 0 5 10 15 20
1.0
1.5
2.0
Health Period 2: 1985-88
Carstairs
Rela
tive R
isk
-5 0 5 10 15 20
1.0
1.5
2.0
Health Period 3: 1989-92
Carstairs
Rela
tive R
isk
-5 0 5 10 15 20
1.0
1.5
2.0
Health Period 4: 1993-96
Carstairs
Rela
tive R
isk
-5 0 5 10 15 20
1.0
1.5
2.0 Respiratory deaths
Cardiovascular deathsAll deaths
Mortality and deprivation for four time periods:
urban wards, UK
Year Unadjusted
Adjusted
1981-84 1.11 1.06
1985-88 1.09 1.07
1989-92 1.05 1.06
1993-96 1.14 1.16
Adjusted and unadjusted risks of respiratory mortality for a 10
ppb increase in SO2
Outcome Mean 1% 99% Mean 1% 99%
Neural tube defects
1.07 1.02 1.12 1.05 1.01 1.10
Hypospadias/ epispadias
1.03 1.00 1.065 1.07 1.04 1.10
Abdominal wall defects
1.16 1.08 1.27 1.08 1.01 1.15
Stillbirths 1.04 1.02 1.05 1.00 0.99 1.02
Low birth weight
1.10 1.095 1.104 1.05 1.047 1.055
Very low birth weight
1.07 1.06 1.08 1.04 1.03 1.05
Abdominal wall defects*
1.13 1.03 1.24 1.07 0.98 1.18
Gastroschisis/ exomphalos*
1.26 1.12 1.42 1.19 1.05 1.34
Unadjusted Adjusted
Landfills: relative risks for ‘exposed’ versus ‘unexposed’
Outcome Mean 1% 99% Mean 1% 99%
Neural tube defects
0.98 0.82 1.16 1.05 0.99 1.10
Hypospadias/ epispadias
1.08 0.98 1.19 1.05 1.02 1.09
Abdominal wall defects
1.24 0.97 1.60 1.06 0.98 1.14
Stillbirths 1.01 0.96 1.06 1.02 1.00 1.03
Low birth weight
1.01 0.99 1.02 1.07 1.062 1.072
Very low birth weight
0.98 0.94 1.02 1.04 1.03 1.05
Abdominal wall defects*
2.26 1.23 4.15 1.12 1.01 1.25
Gastroschisis/ exomphalos*
1.33 0.46 3.81 1.24 1.09 1.42
Before operation During/after operation
* Hospital admissions
Landfills: relative risks for ‘exposed’ versus ‘unexposed’
Health outcome Direction Comment
Traffic accidents +Stronger for pedestrians
Lung cancer + Smoking related
Asthma — Weak
Cardio-vascular illness +
Pulmonary illness +
Congenital malformations
+ Limited evidence
All-cause mortality +
Non-lung cancers — Variable
Communicable diseases
+
Socio-economic deprivation and health
Affluent
Deprived
Exposure
Mort
alit
y
Socio-economic confounding
Deprived
Affluent
Deprived
Exposure
Mort
alit
y
Effect modification
Principle component 1 = traditional aspects of social deprivation; accounts for ca. 57% of the variation in the data and is closely associated with smoking
Principle component 2 = measures relating
to assets and income; accounts for ca. 15%
of the variation in the data
Question 3. How does environmental injustice
work?• What are the mechanisms by which socio-
economic status affects health?
• How do these combine/interact with environmental exposures to affect health?
• What aspects/components of SES?
• What aspects/components of environmental exposure
• Are they necessarily geographical?
• Is it the same everywhere (cultural determinants)?
• How do we study environmental injustice?
Well-being
Morbidity
Mortality
Exposure
Ambient environment
Community
Home
Health outcome
Preventive actions
Remedial actions
Actions
Contexts
Distal
Proximal
Less severe
More severe
Social conditions
Economic conditions
Demographic conditions
causes
attributable to
The ME-ME
Model
Physical injuries
Respiratory illness
Cognitive disfunction
Cardio-vascular disease
Ambient air
pollution
Noise pollution
Traffic accidents
Time activity
Indoor air pollution
Traffic density
Traffic speed
Indoor sources
Housing quality
Road conditions
Smoking
Exposure
Industrial emissions
Emission sources Proximity
Education
‘Road sense’
Diet
Socio-economic factors
Physical injuries
Respiratory illness
Cognitive disfunction
Cardio-vascular disease
Ambient air
pollution
Noise pollution
Traffic accidents
Time activity
Indoor air pollution
Traffic density
Traffic speed
Indoor sources
Housing quality
Road conditions
Smoking
Exposure
Industrial emissions
Emission sources Proximity
Education
‘Road sense’
Diet
Socio-economic factors
Diet
Questions 4+
What conceptual models do we have?
What IS environmental injustice?
What does it mean?
• For epidemiology
• For policy
• For the way we look at the world