Sanitation improves health but not stunted growth: Stanford and icddr,b
With a surprising discovery scientists from icddr,b and Stanford have found that improving water, sanitation and hygiene in resource poor settings of Bangladesh helped overall health but, contrary to expectations, did not improve children's growth and development.
Despite mounting research over the last decade linking poor sanitation to stunted growth in children, a new study found that children born into housing compounds with improvements in drinking water quality, sanitation and hand washing infrastructure were not measurably taller after two years compared to those born into compounds with more contamination - although children who received the interventions were significantly healthier overall.
Commenting on the efficacy of WASH interventions in improving stunted growth Dr. Luby said, "Part of what we learned is that this problem of stunting is not going to be easily fixed by a little bit of attention to water, sanitation and hygiene. Modest efforts to marginally improve environments are not going to be sufficient. If we want children in the lowest-income, most resource-constrained environments to thrive, we're going to need to make their environments radically cleaner."
Children in the Bangladesh trial who received nutritional supplements in addition to WASH interventions did grow taller and were less likely to die, but WASH interventions alone did not improve growth.
The study, published on January 29, 2018 in The Lancet Global Health, examined the health and growth of children from over 5,000 pregnant women in rural Bangladesh after two years. The mothers were grouped according to geographic clusters and randomly assigned to one of six interventions or acontrol group. The six interventions included: i) integration of chlorinated drinking water; ii) upgraded sanitation facilities; iii) promotion of handwashing; iv) a combination of chlorinated drinking water, upgraded sanitation and handwashing promotion (WASH) efforts; and v) nutritional supplements; or iv) WASH and nutritional supplements.
After two years, nearly all the interventions reduced diarrhoea. Although expected, the result is important because it suggests that families did adhere to the interventions. It also creates hope that WASH interventions could beat back one of the greatest killers of children globally - the World Health Organization estimates 361,000 children under 5 years of age die as a result of diarrhoea each year.
Of all the interventions, providing nutritional supplements in addition to combined water, sanitation and hand washing interventions had the greatest effect on curbing mortality, in addition to improving growth. Children receiving this intervention were 38 percent less likely to die compared to children in the control group.
Past research has shown that WASH strategies are effective at reducing diarrhoea and improving child health, Dr. Luby said, but evidence of the impact of these strategies on child growth and development has been sparse.
In response to this lack of data, Dr. Luby began laying the groundwork for the current study more than a decade ago. One of his concerns was ensuring the group developed a rigorous and transparent trial design that included close community partnerships and innovative ways of encouraging village residents to adopt new behaviours. Unless most people in the community adopted the interventions, he knew the results would not be conclusive.
With the large number of children in the study, good adoption of the interventions and careful design, the study had the statistical power to detect small effects. Thus, Dr. Luby noted the absence of growth improvement with WASH interventions was genuine.
"We developed an intervention that the community really liked and were able to achieve really high uptake," said Dr. Luby, who is also director of research for Stanford Global Health. "What this tells us is that these interventions, even with high uptake, likely didn't clean the environment enough to impact child growth. This is a disappointment, but it also helps to provide direction as a way forward."
Commenting on the findings, Dr Md. Mahbubur Rahman, icddr,b principal investigator of the study in Bangladesh, said, "It was shown again that conventional WASH intervention strategies are insufficient to improve stunting in children living in water, sanitation and hygiene compromised settings."
He feels it is the time to think about more comprehensive strategies for WASH interventions that can better ensure clean and safe environments for growing children.
The research was supported by the Bill & Melinda Gates Foundation. Co-authors of the publication include scientists from the International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh; the University of California, Berkeley; the Johns Hopkins Bloomberg School of Public Health; the University of California, Davis; the University of Buffalo; and Emory University.