: 3/30/2004
: 76
: English
/ : World
: Water Supply and Sanitation
Health, Nutrition and Population
: Mariam Claeson
Lorna Fewtrell
Rachel Beth Kaufmann
It is well known that water supply, sanitation and hygiene education can improve health, but controversies persist about the relative importance of these factors. Is water quantity more important than water quality? Is sanitation more important than water supply? Is hygiene more important than hardware? And how does the impact compare to those from other "health" implications? Lorna Fewtrell of the Centre for Research into Environment and Health conducted a review that examined evidence from intervention trials over the past 45 years. The review used a meta-analytic technique to combine data from multiple studies into summary findings for each type of intervention. She presented the findings before a group of Bank public health specialists.
Rachel Beth Kaufmann, a senior public health specialist with the Bank’s South Asia region, and Mariam Claeson, a lead public health specialist in the Bank’s Human Development network, provided introductory remarks. Claeson said it was important to understand where the successful interventions were since resources were limited. Fewtrell said diarrhea remains a highly lethal disease in the developing world, especially for children. The key preventative action is clean water and sanitation services. She discussed an early 1990s study of diarrhea in countries with different sanitation systems that has been an important to subsequent research. Fewtrell said her study focuses on interventions. She looked at water quality and quantity, hygiene and drinking water. To maximize the number of studies that she could access, Fewtrell said she used morbidity rather than mortality as her criteria. She discussed some of the intervention criteria for hygiene, sanitation and water supply. Study periods, sample size, data collection methodologies varied substantially. The standard for study design, she said, is randomized, double blind trial. She then discussed relative risk adjustments. Meta- analysis uses statistical pooling of data to provide overall summary results. Fewtrell showed the stratification for developing countries for water, sanitation and hygiene. The research looked at pre-intervention scenarios for water and sanitation. Water sources and quality, and sanitation conditions varied widely. The data quantified rural and urban situations. Quality issues also were important. She discussed some of the difference between fixed and random effects models.
Some 60 studies were used to do the research. Water quality is the most popular intervention that was studied. Where there was no result or 95% confidence intervals, it could not be used in the meta analysis Fewtrell had described earlier. Only 11 studies were used in the meta analysis. She cited some of the findings. Hand washing is more effective than hygiene education on diarrhea reduction than dysentery. Under several scenarios, diarrhea was reduced markedly, as much as 44%. There were few sanitation studies, only two were used for the meta analysis. For water supply, she showed analysis for its impact on cholera and diarrhea. Hygiene seemed to be an added activity after water and sanitation had been improved in an area. Fewtrell said whenever hygiene is added, it is an effective intervention. She said there is a need for a good quality study on sanitation. Little data on water usage existed, she noted. Household connections probably play a more important role than village connections. She also noted that household storage had an important impact on hygiene and morbidity. More data is needed on water usage. Sustainability of interventions remains a question mark.
RELATED MATERIALS
* Water, sanitation and hygiene: interventions and diarrhoea – a review (PPT)
RELATED B-SPAN EVENTS
* Water Supply and Sanitation (31)
* Health, Nutrition and Population (116)
RELATED WORLD BANK LINKS
* Education and Water: Trying Harder but Could Do Better
* Determinants of Child Morbidity and Mortality in China
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