open defecation and hemoglobin deficiency in young children
Diane Coffeyrice, a research institute for compassionate economics
Office of Population Research, Princeton University
Centre for Development Economics, Delhi School of Economics
prepared for Child Height & Disease Conference,
Aug. 2 & 3, 2013
what is hemoglobin deficiency?
hemoglobin is a protein in red blood cells that carries oxygen
hemoglobin deficiency is a marker of anemia
anemia is defined having hemoglobin concentration below a threshold◦11 gm/dL blood for kids (WHO, 2005)
why does it matter?consequences in adults
◦ reduced work capacity (Basta et al., 1979; Thomas et al., 2004)
◦maternal survival (Rush, 2000)consequences in children
◦ increased susceptibility to infection (Scrimshaw, 2000)
◦ impaired cognitive ability (Grantham McGregor & Ani, 2001)
◦ impaired physical development (Walter et al., 1989)
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WHO (2005) estimated anemia preva-lence among children under five
hypothesis:
open defecation is a cause of hemoglobin
deficiency
outline
background3 analyses
◦1. cross country results◦2. cross sectional results from India &
Nepal◦3. fixed effects results from Nepal
summary, implications for policy & next steps
background
causes of hemoglobin deficiency in young children
• malaria• intestinal parasites• environmental enteropathy• dietary deficiencies
on diet and disease, see Friis et al., 2003
background
links between OD & hemoglobin
• open defecation spreads intestinal parasites – worms live in feces– feces on the ground get onto feet and into mouths– this has been known since at least the 1930s
(Cairncross, 2003)• open defecation exposes kids to fecal
pathogens that could lead to enteropathy
background
links between height & hemoglobin
• this study is consistent with other research on open defecation and height– open defecation thought to cause stunting
through enteropathy and diarrhea• research indicates that hemoglobin deficiency
causes children to be shorter and thinner– larger bodies need more red blood cells to
transport oxygen (see Owen, 1989)
background
3 analyses
1. cross country analysis
data
• hemoglobin: Demographic & Health Surveys from 45 countries– 81 surveys have kids 6-35 months– surveys date from 1995 – 2012– almost 60% of surveys are from SSA
• GDP/capita: Penn World Tables• malaria: WHO incidence estimates (Korenromp, 2005)
cross country analysis
identification
how are open defecation levels across countries and years associated with
hemoglobin levels across countries and years?
cross sectional analysis
open defecation predicts average hemoglobin across countries
specification
• hcry is the average gm/dL of hemoglobin of children 6-35 months in country c, in region r, in year y
• odcry is the fraction of households openly defecating in country c, in region r, in year y
• mcr2004: the country’s estimated incidence of malaria (new cases per year/number of people at risk)
• GDPcry: country and year specific per capita GDP
• y : year fixed effects
cross country analysis
open defecation predicts average hemoglobin across countries
additional specifications (not shown)
• use log of open defecators per square kilometer as an independent variable
• use the 77 country years with hemoglobin measures for kids aged 6 to 59 months
cross country analysis
2. cross sectional analysis from India & Nepal
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Southern
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India (uses
data fro
m 1992 & 2005)
Nepal
(uses data
from 2006 &
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frac
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itat
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open defecation is worst in South Asia
from: WHO & Unicef Joint Monitoring Report, 2012
data• India’s National Family Health Survey 3 (2005)
– 36,000 kids 6-59 months with hemoglobin data– 26,000 kids with hemoglobin & food intake data
• Nepal’s Demographic & Health Survey (2011)– 2,100 kids with hemoglobin data– 1,000 kids with hemoglobin & food intake data
cross sectional analysis: India & Nepal
identification
how is open defecation across places within South Asian countries associated
with hemoglobin levels of children in those places?
cross sectional analysis: India & Nepal
summary statistics
specification
• hip is the hemoglobin (gm/dL) of child i in primary sampling unit (PSU) p
• odp is the fraction of households openly defecating in the child’s PSU
• Mip (medicine): does the child take iron supplements?; did she take de-worming medicine in last 6 months?
• Fip (food): breast feeding; number of time fed solid/semi-solid food in last 24 hours; ate meat in last 24 hours; ate dark green leafy vegetables in last 24 hours
cross sectional analysis: India & Nepal
• elecp is the fraction of households in the child’s PSU with electricity
• urbanp is whether or not the child’s PSU is urban
• Eip (mother’s education): linear or dummy variable controls for mother’s education
• SESip (socioeconomic status): child’s household wealth percentile, or asset ownership dummies
• (AipXsexip): 120 sex-specific age-in-month indicators
cross sectional analysis: India & Nepal
open defecation predicts hemoglobin in India
open defecation predicts hemoglobin in Nepal
3. fixed effects analysis from Nepal
data
• Nepal’s Demographic & Health Surveys from 2006 and 2011– 4,680 kids 6-59 months in 2006– 2,100 kids 6-59 months in 2011
• 15 percentage point drop in open defecation from 2006-2011– about 50% of households (2006) to about 35% of
households (2011)
fixed effects analysis: Nepal
identification
how is change over time in open defecation within 25 urban and rural parts of each DHS region (subsequently referred to as
regions) associated with change in hemoglobin levels in those regions?
fixed effects analysis: Nepal
specification
• hiyr: hemoglobin measure of child i, in year y, in region r
• odyr: fraction of HH openly defecating in the child’s region
• elecyr: fraction of HH with electricity in the child’s region
• y: year of survey fixed effect (indicator for 2011)
• δr: region fixed effect
• Eiyr: indicators for mother’s years of education
• SESiyr: economic status dummies
• (Aiyr X sexiyr): 120 sex-specific age-in-month indicators
fixed effects analysis: Nepal
change in open defecation predicts change in hemoglobin in Nepal
summary, implications for policy & next steps
summarydiscussed two mechanisms through
with open defecation could impact hemoglobin◦parasites◦environmental enteropathy
presented results of 3 analyses which support an effect of open defecation on hemoglobin◦cross country results from 81 surveys◦cross sectional results from India & Nepal◦fixed effects results from Nepal
implications for policy (1 of 3)
This study provides econometric evidence
that open defecation may be an important cause of hemoglobin deficiency.
implications for policy (2 of 3)
It suggests that current efforts to improve
hemoglobin by supplementing diets and fortifying foods could be
importantly complemented by
sanitation provision.
implications for policy (3 of 3)
This study adds to a growing body of research
that shows the importance of sanitation for nutrition, particularly
in South Asia.
next steps for this project
compare effect sizes with those associated with other causes of hemoglobin deficiency
control for variation in malaria exposure within South Asia
explore the effect of open defecation on hemoglobin among women
your ideas…?
questions? comments?
hemoglobin level by age in India & Nepal
summary statistics
haemoglobin!