Ollie stunting & sanitation conference oliver cumming
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Transcript of Ollie stunting & sanitation conference oliver cumming
Linking toilets to stunting
Sanitation and Stunting Conference, Delhi School of EconomicsJuly 2013
Oliver CummingEnvironmental Health GroupLondon School of Hygiene and Tropical Medicine
Stunting – a global challenge
Short-term• ↑ risk of mortality• ↑ susceptibility to infections/morbidityLong-term• Educational achievement• Work capacity• Economic productivity
34 countries which account for 90% of undernutrition. Source: Bhutta et al, 2013
Growth faltering
Mean height for age z-scores by age by region
Source: Victora et al 2010
Age 2
And, in India
SOURCE: Reproductive health, and child health and nutrition in India: meeting the challenge. Paul et al (Lancet 2011)
A tough nut to crack
SOURCE: Lancet Series on Maternal and Child Undernutrition and Overweight (Black et al, 2013)
Nutrition-specific interventions
If 10 core nutrition specific interventions were scaled up at 90% coverage, could reduce stunting by 20%(Bhutta et al 2013)
How do we close the gap?
Nutrition-sensitive interventions
What is the contribution of sanitation and
water… and hygiene?
Linking WASH to undernutrition
Faecal-oral exposure
Diarrhoeal Diseases
Environmental Enteropathy
Nematode infection
Poor WASH
Poor nutritional status
Diarrhoea and stunting
Diarrhoea is associated with poor nutritional status but causal link is hard to demonstrate
Recent analysis of 9 studies with daily diarrhoea morbidity data and longitudinal anthropometry (Checkley et al, 2008):
Odds of stunting at age 24 months increased by 1.13 (95% C.I. 1.07, 1.19) for every five episodes
Consistent with a hypothesis that higher cumulative burden of diarrhoea increases risk of stunting
Nematode infections
Parasitic worm infections associated with poor sanitation that limit growth and cognitive development:
• Ascaris lumbricoides (Roundworm)Intestinal obstruction & Vit A malabsorption
• Trichuris trichiura (Whipworm)Dysentery syndrome, colitis
• N. americanus & A. duodenale (Hookworm)Intestinal blood loss, iron deficiency, PEM
SOURCE: Bethony et al, 2006
Environmental Enteropathy
• Villous atrophy• Crypt hyperplasis• Increased gut permeability• Inflammatory cell infiltration
• Malabsorption• Blunted immune function• Oral vaccine failure
SOURCES: Images - Garcia, 1968; Histology – Humphrey 2009; Korpe & Petri
What does this mean for India?
Diarrhoea A leading cause of child deaths (13% of all u-5)
Nematode infections284 million nematode infections
Environmental enteropathy Plausibly high prevalence but not measured
SOURCE: Reproductive health, and child health and nutrition in India: meeting the challenge. Paul et al (Lancet 2011)
1. Stunting is very important and a major public health challenge in India
2. Scaling up nutrition-specific interventions alone not sufficient
3. Plausible that limiting faecal-oral exposure will reduce stunting
4. What evidence is there that WASH is effective in reducing stunting?
Recap…
What did we review?• All included studies had an intervention and control
– RCTs, BACC, ITS
• Participants: children < 5
• All WASH interventions
• Outcomes: z-scores and other anthropometric and bio-markers
• 6 databases searched; keyword and MeSH terms
• 3 main Chinese databases searched
Search results - HAZ
Included studies
• 14 studies from 10 countries (but not India)• 5 appropriate for meta-analysis• Duration: 6 months to 5 years• Sample: n=11,611; all children <5 years• Multiple WASH interventions• Multiple study designs (including 5 RCTs)• No study considered to be “high quality”
HAZ meta-analysis
Supported by a separate individual participant data analysis (IPD):
HAZ: Mean Diff 0.11 z-score (95% CI: 0.03, 0.18)
Interpretation
• Cochrane meta-analysis suggests effect of WASH of mean difference 0.08 HAZ z-score (borderline significant)
• Approx. equivalent to 0.5 cm at 5 years of age
• Approx. equivalent to a relative decline in stunting of as much as 15%* (absolute decline of 4.5%)
• No sanitation, no water supply…
Sanitation and stunting in India
1. Stunting is an enduring challenge in India with far-reaching consequences and f/o exposure may be an important factor
2. Suggestive evidence that WASH is effective in reducing stunting
3. Rethink design and targeting of some environmental (‘WASH’) interventions
4. New evidence will help strengthen our response (Orissa RCT)
5. Don’t forget the basics – people need to own and use toilets!
Acknowledgements
Collaborators:Dr Alan Dangour, Louise Watson and other co-authors
Funders:UK Department for International Development
Further information:www.SHAREresearch.org
http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009382.pub2/full
Thank you!