Review
Effects of sanitation on cognitive development and school absence: A systematic review

https://doi.org/10.1016/j.ijheh.2017.06.010Get rights and content

Abstract

Objective

We undertook this systematic review to explore the relationship between sanitation and learning outcomes, specifically cognitive development and absence.

Methods

We searched leading databases to identify experimental and observational studies that address the effect of sanitation on our outcomes of interest. We identified 17 studies that met the review’s eligibility criteria, four reporting on measures of cognitive development, 12 on school absence (with two studies reporting on school and work absence), and one study that reported on both outcomes. We assessed the risk of bias of individual studies as well as the overall strength of evidence for each outcome. Because of fundamental differences among the studies in terms of sanitation exposure and outcome measurement, pooling results via meta-analysis was deemed inappropriate so a descriptive review is presented.

Results

Studies reported that access to household sanitation was associated with measures of improved cognitive ability in children. However, collectively these studies were rated by GRADE as poor methodological quality with significant potential for confounding and bias, including publication bias. Studies on the association between household, community or school sanitation and school absence yielded mixed results. Some sanitation studies reported lower absence while others reported higher absence. Only the two randomized controlled trials reported no overall effects on absence even when combining sanitation with water supply improvements and hygiene promotion. Study quality as assessed by GRADE was again generally poor.

Conclusion

While studies to date provide some support for positive effects from sanitation on cognitive development, the effects on school absence are uncertain. Differences in effects may be due to differences in study settings, type of sanitation exposure and most notably in outcome definitions. Further research in multiple settings using rigorous study designs and measuring intermediate outcomes such as exposure can help determine the effects of sanitation on these important learning outcomes.

Introduction

Almost one billion people currently lack access to sanitation (UNICEF, 2015). Most live in rural settings in developing countries and practice open defecation. Systematic reviews on the health impacts of sanitation have focused on anthropometric outcomes (Dangour et al., 2013; Freeman et al., submitted) or on infectious disease outcomes, such as diarrhoea, trachoma, soil transmitted helminth infection and schistosomiasis (Clasen et al., 2010; Freeman et al., submitted; Grimes et al., 2014, Stocks et al., 2014, Strunz et al., 2014, Wolf et al., 2014). The World Health Organization (WHO), however, defines health not only as the absence of disease but as a “state of complete physical, mental and social well-being.” Sanitation has the potential to address not only infectious disease but various aspects of well-being, such as reaching one’s full potential through proper cognitive development and the ability to attend school and work.

Researchers have begun to explore the different causal pathways for these learning outcomes. In one pathway, researchers theorize and initial studies show that access to sanitation lowers rates of sanitation-related illnesses and as a result, may lead to better cognitive ability and a healthier state to attend school or work (Khalil et al., 2016, Pinkerton et al., 2016, Watanabe and Petri, 2016) (Fig. 1–A). Even reductions in asymptomatic but repeated enteric infections, known as environmental enteropathy, has been linked to improvements in early childhood development (Kosek, 2017). In another pathway specific to the school setting, access to adequate school sanitation creates a comfortable learning environment which may lower rates of student absence and ultimately lead to better school performance (Pearson and McPhedran, 2008) (Fig. 1–B). Several studies in low and middle-income countries have also explored the connection between adequate school sanitation and attendance rates of postmenarcheal girls who require sanitation facilities to hygienically and comfortably manage their menstruation (Boosey et al., 2014, Haver et al., 2013, Long et al., 2013, Pearson and McPhedran, 2008, Phillips-Howard et al., 2016, Sommer, 2010). The purpose of this review is to assess the impact of sanitation, be it access, quality or a specific sanitation intervention at the household, school or community level, on cognitive development and absence from school or work.

The WHO commissioned this systematic review as part of its effort to develop the evidence base for a set of guidelines on sanitation and health. This review is one of three reviews on the impact of sanitation on different health outcomes: sanitation-related infectious diseases and nutritional status (Freeman et al., submitted), wellbeing (Sclar et al., unpublished results), and the current two outcomes of interest − cognitive development and absence from school or work. Since only two eligible studies examined both school and work absence, we describe cognitive development and absence as ‘learning outcomes’ throughout this review. In addition, although the literature to date often uses the term “absenteeism” to describe this learning outcome, “absenteeism” specifically refers to missing school or work on a regular basis and often without a suitable reason like illness. As such, we use the term “absence” which more generally refers to the act of missing school or work. These reviews on sanitation and aspects of health are part of a series of systematic reviews that also examine the impact of different sanitation interventions on latrine coverage and use (Garn et al., 2016) and the impact of sanitation on transmission pathways (Sclar et al., 2016a).

Section snippets

Search strategy

We searched the literature to identify relevant studies that address the impact of sanitation on measures of cognitive development and absence (see Supplemental Text S1 for protocol and Supplemental Text S2 for PRISMA Checklist). Our search included studies published in English, Spanish, Portuguese, French, German or Italian with any publication status (published, unpublished, in press, grey literature, etc.) written between 1950 and December 2015. We conducted our search in English and used

Search results

Execution of the search strategy yielded 10,013 titles and abstracts. After screening, two reviewers examined the full text of 528 studies for further assessment. Of these, 17 studies met the review’s eligibility criteria (Fig. 2). Four of these studies reported only on measures of children’s cognitive development (Table 2), 12 reported on children’s school absence (Table 3), and one study reported on both. The majority of eligible studies (N = 11) were published in the last five years,

Discussion

Sanitation has the potential to impact many aspects of health. Among the possible effects of improved sanitation at home or in the school setting, are improvements in cognitive development and school attendance. The former is hypothesized as an indirect effect of reduced insults from pathogenic agents, especially in regards to environmental enteropathy (Khalil et al., 2016, Kosek, 2017, Pinkerton et al., 2016, Watanabe and Petri, 2016), while the latter are believed to be drawn both from

Acknowledgements

We are grateful to Darcy Anderson, Henrietta Lewis, Amrita Mahtani, Divya Narayanan, and Rachel Stelmach for their work on the title, abstract, and full text review. We are also grateful to Darcy Anderson and Amrita Mahtani for their assistance on data extraction and the risk of bias assessments. Finally, we would like to acknowledge funding support for this review from the World Health Organization.

References (43)

  • R. Boosey et al.

    Menstrual hygiene management amongst schoolgirls in the Rukungiri district of Uganda and the impact on their education: a cross-sectional study

    Pan. Afr. Med. J.

    (2014)
  • L. Cameron et al.

    Impact Evaluation of a large-scale rural sanitation project in Indonesia

  • B.A. Caruso et al.

    Assessing the impact of a school-based latrine cleaning and handwashing program on pupil absence in Nyanza Province, Kenya: a cluster-randomized trial

    Trop. Med. Int. Health

    (2014)
  • T.F. Clasen et al.

    Interventions to improve disposal of human excreta for preventing diarrhoea

    Cochrane Database Syst. Rev.

    (2010)
  • A.D. Dangour et al.

    Interventions to improve water quality and supply, sanitation and hygiene practices, and their effects on the nutritional status of children

    Cochrane Database Syst. Rev.

    (2013)
  • A. Das

    Exploring the pattern and determinants out-of-schools at elementary level i India

    Int. J. Child Adolescent Health

    (2011)
  • M.C. Freeman et al.

    Assessing the impact of a school-based water treatment, hygiene and sanitation programme on pupil absence in Nyanza Province, Kenya: a cluster-randomized trial

    Trop. Med. Int. Health

    (2012)
  • Freeman, M.C., Sclar, G.D., Garn, J.V., Alexander, K.T., Penakalapati, G., Anderson, D., Grimes, J., Mahtani, A.,...
  • J.V. Garn et al.

    The impact of sanitation interventions on latrine coverage and latrine use: a systematic review and meta-analysis

    Int. J. Hyg. Environ. Health

    (2016)
  • M. Grant et al.

    Menstruation and school absenteeism: evidence from rural Malawi

    Comp. Educ. Rev.

    (2013)
  • J.E. Grimes et al.

    The relationship between water, sanitation and schistosomiasis: a systematic review and meta-analysis

    PLoS Negl. Trop. Dis.

    (2014)
  • Cited by (0)

    View full text