sanitation externalities, disease and children’s anemia diane coffey office of population...
TRANSCRIPT
sanitation externalities, disease and children’s anemia
Diane CoffeyOffice of Population Research, Princeton University
prepared for PAA session on Public Health & Demography,
May 2, 2014
what is anemia?
hemoglobin: a protein in red blood cells that carries oxygen
anemia: lack of hemoglobin◦hemoglobin concentration below 11
gm/dL blood (WHO, 2005) in children
why does anemia matter?
Scrimshaw, 2000: increased susceptibility to infection
Grantham McGregor & Ani, 2001: impaired cognitive ability
Walter et al. 1989: impaired physical development
Stevens et al., 2011: globally, 43% of children anemic; 58% in South Asia
causes of anemia
diet: iron, vitamin B12, folate
diseases◦intestinal parasites◦environmental enteropathy◦malaria
blood loss
hypothesis
lack of sanitation (open defecation)
causes disease that contributes to
anemia
outlinebackground
◦why is this link plausible?◦sanitation externalities
empirical results◦ cross country gradient◦ cross sectional results from India & Nepal◦ fixed effects results from Nepal
policy implications◦does poor sanitation make other
interventions less effective?
background
why is this link plausible?diseases caused by open defecation
• intestinal parasites – feces on the ground spread parasites that
enter kids’ bodies by the feet and mouth (Rosenberg & Bowman, 1982)
• environmental enteropathy – bacteria in feces reduces absorptive
capacity of intestines (Walker, 2003; Humphrey, 2009)
background
why is this link plausible?open defecation and height
• growing literature in economics and epidemiology finds effects on height– Bangladesh: Lin et al., 2013– Indonesia: Cameron et al., 2013– India: Hammer & Spears, 2012– international: Spears, 2012
• height and hemoglobin could be influenced by similar intestinal diseases
background
sanitation externalities
Observations are children in India’s 2005 DHS.
empirical results
cross country gradient
data• hemoglobin & open defecation: DHS
– 81 surveys from 45 countries– 1995 – 2012– 60% of surveys are from SSA
• GDP per capita & population density: Penn World Tables & World Bank
• malaria: WHO incidence estimates (Korenromp, 2005)
cross country motivation
R2 = 0.23
density of open defecation and hemoglobin in 81 DHS
R2 = 0.26
open defecation density and hemoglobin in 81 DHS – net of malaria
R2 = 0.43
regression gradients: density of open defecation & hemoglobin
no controls + malaria + per capita GDP + year fixed effects
-0.25
-0.2
-0.15
-0.1
-0.05
0
fixed effects results from Nepal
data
• Nepal’s Demographic & Health Surveys from 2006 and 2011– 2006: 4,680 kids 6-59 months– 2011: 2,100 kids 6-59 months
• 15 percentage point drop in open defecation– 2006: 50% of households – 2011: 35% of households
fixed effects results
identification
how is change over time in open defecation within 25 regions
associated with change in hemoglobin levels in those
regions?
fixed effects results
change over time in open defecation within Nepali regions predicts change in hemoglobin
policy implications
in India, associations between parasite medicine and hemoglobin and iron pills and hemoglobin are
weaker where there is more open defecation
difference in hemoglobin levels between kids who took parasite medicine and those who did not
difference in hemoglobin levels between kids who took iron pills
and those who did not
0
0.2
0.4
0
0.2
0.4
summary
This study adds to a growing body of research
that shows the importance of sanitation for nutrition, particularly
in South Asia.
This study provides econometric evidence that open defecation
may spread diseases that cause anemia.
summary
It suggests that efforts to improve anemia by
supplementing diets and treating parasites could
be importantly complemented by
greater attention to sanitation.
summary
questions? comments?
the association between parasite medicine and hemoglobin is greater where there is less open defecation
difference = 0.4 gm/dL
difference = 0.2 gm/dL
10% 90%