Sanitation and Hygiene-Specific Risk Factors for Moderate-to-Severe Diarrhea in Young Children in the Global Enteric Multicenter Study, 2007–2011: Case-Control Study

Abstract

Background

Diarrheal disease is the second leading cause of disease in children less than 5 y of age. Poor water, sanitation, and hygiene conditions are the primary routes of exposure and infection. Sanitation and hygiene interventions are estimated to generate a 36% and 48% reduction in diarrheal risk in young children, respectively. Little is known about whether the number of households sharing a sanitation facility affects a child's risk of diarrhea. The objective of this study was to describe sanitation and hygiene access across the Global Enteric Multicenter Study (GEMS) sites in Africa and South Asia and to assess sanitation and hygiene exposures, including shared sanitation access, as risk factors for moderate-to-severe diarrhea (MSD) in children less than 5 y of age.

Methods/Findings

The GEMS matched case-control study was conducted between December 1, 2007, and March 3, 2011, at seven sites in Basse, The Gambia; Nyanza Province, Kenya; Bamako, Mali; Manhiça, Mozambique; Mirzapur, Bangladesh; Kolkata, India; and Karachi, Pakistan. Data was collected for 8,592 case children aged <5 y old experiencing MSD and for 12,390 asymptomatic age, gender, and neighborhood-matched controls. An MSD case was defined as a child with a diarrheal illness <7 d duration comprising ≥3 loose stools in 24 h and ≥1 of the following: sunken eyes, skin tenting, dysentery, intravenous (IV) rehydration, or hospitalization. Site-specific conditional logistic regression models were used to explore the association between sanitation and hygiene exposures and MSD. Most households at six sites (>93%) had access to a sanitation facility, while 70% of households in rural Kenya had access to a facility. Practicing open defecation was a risk factor for MSD in children <5 y old in Kenya. Sharing sanitation facilities with 1–2 or ≥3 other households was a statistically significant risk factor for MSD in Kenya, Mali, Mozambique, and Pakistan. Among those with a designated handwashing area near the home, soap or ash were more frequently observed at control households and were significantly protective against MSD in Mozambique and India.

Conclusions

This study suggests that sharing a sanitation facility with just one to two other households can increase the risk of MSD in young children, compared to using a private facility. Interventions aimed at increasing access to private household sanitation facilities may reduce the burden of MSD in children. These findings support the current World Health Organization/ United Nations Children's Emergency Fund (UNICEF) system that categorizes shared sanitation as unimproved.

Abstract

In a matched case-control study, Kelly Baker and colleagues explore the association between sanitation and hygiene exposures and moderate-to-severe diarrhea in young children in Africa and South Asia.

Editors' Summary

Background

Diarrhea—passing three or more loose or liquid stools per day—is a leading cause of death among children under 5 y old. Diarrhea, which can cause severe dehydration, kills about three-quarters of a million young children every year, mainly in resource-limited countries. Frequent bouts of diarrhea also cause long-term damage to the gut, malnutrition, and growth stunting. Diarrhea is a common symptom of gastrointestinal infections. The enteric pathogens (viruses, bacteria, and parasites infecting the gut) that cause diarrhea spread through contaminated food or drinking water and through poor hygiene (for example, failure to wash one’s hands after using the toilet) and inadequate sanitation (unsafe disposal of human excreta). Improvements in water, sanitation, and hygiene can reduce exposure to enteric pathogens, thereby reducing the incidence of diarrhea among young children. For example, access to an improved sanitation facility reduces the risk of diarrhea in young children by up to 36%.

Why Was This Study Done?

In 2000, world leaders agreed to reduce the proportion of the global population without access to safe drinking water and basic sanitation to half of the 1990 level by 2015 as part of Millennium Development Goal (MDG) 7; the MDGs were designed to eradicate extreme poverty globally. To measure progress towards MDG7, the WHO/UNICEF Joint Monitoring Programme (JMP) currently defines an improved sanitation facility as an unshared facility that hygienically separates human excreta from human contact (for example, a flush toilet or a pit latrine). Facilities of an improved type that are shared by multiple households are classified by the JMP as unimproved because of worries that shared facilities are less hygienic and less accessible than private household facilities. However, some experts suggest that the JMP guidelines should be changed to allow facilities shared by five or fewer households to be considered as improved facilities if they meet the other criteria for separating human excreta from human contact. But does sharing a sanitation facility affect a child’s risk of diarrhea? Here, the researchers investigate this question by analyzing data collected by the Global Enteric Multicenter Study (GEMS).

What Did the Researchers Do and Find?

GEMS is a case-control study, an observational study that compares the characteristics of people with a specific disease with those of people without that disease. It collected data on 8,592 children under 5 y old with moderate-to-severe diarrhea (MSD; experiencing diarrhea at least three times in 24 h with signs of moderate-to-severe dehydration or hospitalization) and 12,390 healthy children matched for age, gender, and location at seven sites in Africa and South Asia. Most of the households (>93%) at six of the sites had access to a sanitation facility, whereas only 70% of households at the Kenyan site had access to a facility. Compared to having a private household sanitation facility, sharing a facility with three or more households significantly increased the risk of young children developing diarrhea (a significantly increased risk is unlikely to have occurred by chance) at the study sites in Kenya, Mali, Mozambique, and Pakistan. At the sites in Kenya, Mali, and Pakistan, sharing a facility with one or two households also increased MSD risk. Sharing a sanitation facility did not increase MSD risk at the sites in The Gambia, Bangladesh, or India.

What Do These Findings Mean?

These findings show that sharing a sanitation facility with one or two other households is associated with an increased risk of MSD in young children. Because this was an observational study, these findings only show an association between the use of shared sanitation facilities and MSD risk; they cannot prove that using shared facilities causes diarrhea. It could be, for example, that households who decide to invest in a private sanitation facility also prioritize safe hygiene practices. The reduced risk of diarrhea in these households might then be the result of everyone washing their hands after using the toilet rather than the result of having a private latrine. Nevertheless, these findings suggest that interventions aimed at increasing access to private household sanitation facilities might reduce the global MSD burden. Moreover, they suggest that shared sanitation facilities should continue to be classified as “unimproved” for the purposes of monitoring global access to sanitation.

Additional Information

This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at http://dx.doi.org/10.1371/journal.pmed.1002010.

• This study is further discussed in a PLOS Medicine Perspective by Jonny Crocker and Jamie Bartram

• A PLOS Medicine Collection on water and sanitation is available

• The World Health Organization (WHO) provides information on water, sanitation, and health (in several languages) and on diarrhea

• The WHO/UNICEF JMP is the official United Nations mechanism tasked with monitoring progress toward MDG7, Target C; the JMP Update Report 2015 is available online (key facts are available in several languages through the JMP website)

• The children’s charity UNICEF, which protects the rights of children and young people around the world, provides information on water, sanitation, and health and on diarrhea (in several languages)

• The Water Supply and Sanitation Collaborative Council and the non-governmental organization Practical Action provide information and approaches and technologies for improving sanitation

• The Sanitation and Hygiene Applied Research for Equity (SHARE) contributes to knowledge about effective, sustainable, and equitable sanitation and hygiene by supporting research to improve policy and practice worldwide.

• More information about GEMS is available