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%