The impact of sanitation and hygiene on child mortality and health has been underestimated, contends Dr Jean Humphrey in The Lancet of 19 September 2009 [free registration required].
“Of the 555 million preschool children in developing countries, 32% are stunted and 20% are underweight. Child underweight or stunting causes about 20% of all mortality of children younger than 5 years of age and leads to long-term cognitive deficits, poorer performance in school and fewer years of completed schooling, and lower adult economic productivity.”
“A key cause of child undernutrition is a subclinical disorder of the small intestine known as tropical enteropathy”, Dr. Humphrey states, which “is caused by faecal bacteria ingested in large quantities by young children living in conditions of poor sanitation and hygiene”. “Provision of toilets and promotion of handwashing after faecal contact could reduce or prevent tropical enteropathy and its adverse effects on growth”. “The primary causal pathway from poor sanitation and hygiene to undernutrition is tropical enteropathy and not diarrhoea”.
Dr. Humphrey concludes that “that prevention of tropical enteropathy, which afflicts almost all children in the developing world, will be crucial to normalise child growth, and that this will not be possible without provision of toilets”.
Humphrey, J.H. (2009). Child undernutrition, tropical enteropathy, toilets, and handwashing. The Lancet ; vol. 374, no. 9694 ; p. 1032-1035. doi:10.1016/S0140-6736(09)60950-8
In an earlier WHO study, the authors estimated that 860 000 deaths per year in children under five years of age were “caused directly and indirectly by malnutrition induced by unsafe water, inadequate sanitation and insufficient hygiene”. This raises the total number of children that die every year as a result of unsafe water, inadequate sanitation or insufficient hygiene to 2.2 million instead of the 1.4 million usually quoted.
Pruss-Ustun, A.; Bos, R.; Gore, F. and Bartram, J. (2008). Safer water, better health : costs, benefits and sustainability of interventions to protect and promote health. Geneva, Switzerland, World Health Organization (WHO). Read the full report [PDF file].