Environmental Enteropathy Pilot Study Cleaner households are associated with improved gut function in Bangladesh Audrie Lin, PhD Ben Arnold, PhD Sadia Afreen, MPH Jack Colford, MD, MPH, PhD Steve Luby, MD WASH Benefits Team 3 August 2013 Photo: Audrie Lin
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Environmental Enteropathy Pilot StudyCleaner households are associated with improved
Inflammatory disorder of small intestine that reduces nutrient absorption and increases intestinal permeability
Lactulose Mannitol Diagnostic Assay for EE
Lactulose sugar– Too large to be absorbed by healthy intestine– L is a measure of barrier efficacy– EE lactulose absorption
Mannitol sugar– Small and moves across intestine in quantities
proportional to absorptive surface area– M is a measure of absorptive capacity– EE mannitol absorption
Healthy Intestine = Low L:M ratio EE = High L:M ratio
LM Dose
5-Hour Urine Collection
Measure L:M in Urine
Adapted by Christine Stewart from Victora et al., 2010
Critical Period For Growth Faltering
Increase in Lactulose:Mannitol Ratios with Age in Gambian Village Children
1-3 3-6 6-9 9-12 12-15
Age (Months) Lunn 1991
The Gambia
United Kingdom
EE Background Studies
• In Bangladesh, L:M ratio increases from age 3 – 12 months in a rural subdistrict (Goto et al Br J Nutr 2009; Trans Roy Soc of Trop
Med Hyg 2009)
• Enteropathy develops in people who move from more developed countries to more contaminated environments (e.g., Peace Corps volunteers). (Lindenbaum et al. Ann Intern Med 1966)
• Within 17 months after the Peace Corps volunteers’ return to New York City, the biopsies normalized and within 1 to 35 months, most of the volunteers had normal, functioning small intestines. (Lindenbaum et al. Ann Intern Med 1971)
Photo : throbule www.panoeramio.com
Study Question
Is environmental enteropathy a potential mechanism to explain the association between environmental contamination and stunting?
SHEWA-B EvaluationSanitation Hygiene Education and Water Supply, Bangladesh
• Government of Bangladesh / UNICEF program
• Targeting 20 million people• icddr,b contracted with the
evaluation– 50 intervention and 50 matched
control clusters
– Clusters randomly selected
– 10 households per cluster
– Monthly follow up for 2 years
Would Children in Relatively Clean Households Have Less EE Than Children in Dirtier Households?
Dirty Clean
5.4% 6.4%
SHEWA-B WASH Survey• 993 households • July 2007 – Oct 2009
WASH Benefits?
Definitions and Household Selection Criteria
Clean
• flush/septic/piped sewerage or pit latrine with slab & water seal
• [E. coli] < 10 CFU/100 ml
• handwashing station w/ water and soap
Dirty
• open defecation, hanging toilet, open pit latrine, pit latrine with slab but no water seal, or flush/pour to “somewhere else”
• [E. coli] ≥ 10 CFU/100 ml
• No handwashing station or handwashing station w/o water and/or w/o soap
Photo: Flickr zafarbaig08
Illustrations: practicalaction.org
Finding the study children
• SHEWA-B evaluation– 993 households– July 2007 – Oct 2009
• Environmental enteropathy assessment– May 2010– 136 children– 49 sub-districts
Field Research AssistantsShabina YesminLubna TaniTania ZahirMd. Shafiqul HaiderIrin AkterMd. AlimojjamanFatema Begum SumiNurul AlamMahmuda AkterShadia AhmedTowhida AkterAfsana Binte BariRahela Akter
Field AssistantsMd. AlamMd. Mohasin KabirMd. Saiful IslamMd. Jamilur RahmanMd. Shah AlamMd. Aminul IslamMd. Junayed Hossain
Extra Slides
Geography of Environmental Enteropathy
50 – 95% incidence in developing countries McKay 2010, Menzies 1999
Correlation of EE with GDP Per Capita
Menzies 1999
GDP correlates with absorptive capacity GDP correlates with intestinal permeability
Variation in Lactulose:Mannitol Ratio With Age in The Gambia
La
ctu
lose
:Man
nit
ol P
erm
ea
bili
ty R
ati
o
Age Group (Years)Campbell 2002
The Gambia
United Kingdom
Children from Clean Households are 22 percentage points less likely to be stunted
DiffStunting
95% CI P
Unadjusted –0.40 (–0.57, –0.24) <0.001
Adjusted for age + sex –0.42 (–0.59, –0.26) <0.001
Fully Adjusted * –0.22 (–0.42, –0.02) 0.030
Robustness Checks
Mahalanobis matched** –0.25 (–0.46, –0.04) 0.019
GenMatch** –0.28 (–0.50, –0.05) 0.017
* Adjusted for age, sex, housing materials, household electricity, household size, land ownership, household head occupation, durable good ownership (bike, tables, chairs, beds, radio, tv).
** Matching estimators include the adjustment covariates used in fully adjusted models, plus the propensity score estimated using main effects of the covariates.
Enteropathy biomarkersclean versus dirty
Biomarker * Clean Dirty Difference
Mean Mean in SDs 95% CI
Ln Total IgG –0.14 0.16 –0.30 (–0.69, 0.08)
Ln EndoCAb –0.12 0.16 –0.29 (–0.64, 0.07)
Ln L:M Ratio –0.19 0.23 –0.42 (–0.77, –0.07)
* Biomarkers standardized by subtracting the sample mean and dividing by the sample SD.