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!