Water and sanitation interventions for better child health: Evidence from a synthetic review Hugh...

Water and sanitation interventions for better child health: Evidence from a

synthetic review Hugh Waddington Birte Snilstveit Howard White Lorna Fewtrell

3ie

2

Contents

n Objectives

n Methodology

n Results: effectiveness

n Results: sustainability

n Conclusions

3

1. Objectives of the synthetic review

Conduct review to Cochrane/Campbell standards

Mixed methods: analysis of quantitative and qualitative information

Synthesise quantitative information using meta-analysis: assess whether existing ‘consensus’ stands up to inclusion of new studies, and internal and external validity criteria

Theory-based: draw out behavioural and contextual factors shaping success/failure and (likely) sustainability

4

2. Methodology Extensive search (published and unpublished sources)

Inclusion criteria: impact of WSH on diarrhoea; experimental and quasi-experimental methods

Coding of studies: Internal validity: study design; data quality External validity: contextual information Quantitative and qualitative information relating to process, context, behaviour,

confounding, moderation

Effectiveness of interventions assessed using: Meta-analysis (fixed/random effects models; impact heterogeneity, publication

bias) Meta-regression

Sustainability of interventions assessed using quantitative and qualitative information relating to process (outputs), study length and size, replicability

6

3. Results: about the interventionsTotal num

Num RCTs

Total sample

Ave sample

Ave length (months)

Water supply 14 0 64,651 5,877 19

Water treatment 40 27 16,400 586 10

Point of use water treatment (POU)

35 24 11,457 327 7

Source water treatment 5 2 4,943 989 15

Sanitation 13 2 33,682 3,368 16

Hygiene 38 14 29,254 1,083 12

Hand-washing with soap 9 4 12,472 1,386 6

Education 29 10 16,782 579 13

7

Effectiveness: Water supply interventions

NOTE: Weights are from random effects analysis

Overall (I-squared = 75.8%, p = 0.000)

Gasana et al (2002)

Jalan & Ravallion (2003)

Study

Galiani et al (2007)

Pradhan & Rawlings (2002)

Alam et al (1989)

Tonglet et al (1992)

ID

Khanna (2008)

Ryder et al (1985)

0.92 (0.83, 1.01)

1.08 (0.92, 1.27)

0.76 (0.69, 0.84)

0.50 (0.19, 1.31)

0.74 (0.37, 1.49)

0.83 (0.72, 0.96)

0.94 (0.89, 1.00)

ES (95% CI)

0.92 (0.85, 1.00)

1.34 (1.00, 1.80)

0.92 (0.83, 1.01)

1.08 (0.92, 1.27)

0.76 (0.69, 0.84)

0.50 (0.19, 1.31)

0.74 (0.37, 1.49)

0.83 (0.72, 0.96)

0.94 (0.89, 1.00)

ES (95% CI)

0.92 (0.85, 1.00)

1.34 (1.00, 1.80)

Favours intervention 1.25 .5 .75 1 2

8

Effectiveness: Water treatment interventions



Stauber et al (2009)

Kirchhoff et al (1985)

Chiller et al (2006)

Mahfouz et al (1995)

de Wilde et al (2008)

Jensen et al (2003)

Gasana et al (2002)

Lule et al (2005)

Conroy et al (1999)

Semenza et al (1998)

Reller et al (2003)

Austin (1993)

Clasen et al (2005)

du Preez et al (2008)

Sobsey et al (2003)

Rose et al (2006)

Crump et al (2005)

Brown et al (2008)

Kremer et al (2008)

Roberts et al (2001)

Clasen et al (2006)

Brown et al (2007)

Blanton et al (2008)

Luby et al (2004)

Tiwari et al (2009)

Quick et al (1999)

ID

Luby et al (2006)

Clasen et al (2004)

Universidad Rafael Landivar (1995)

Study

0.64 (0.57, 0.72)

0.74 (0.51, 1.07)

0.97 (0.78, 1.21)

0.61 (0.45, 0.83)

0.55 (0.31, 0.99)

1.02 (0.88, 1.19)

0.94 (0.89, 1.00)

0.67 (0.55, 0.81)

0.90 (0.51, 1.59)

0.69 (0.63, 0.75)

0.33 (0.19, 0.57)

0.74 (0.58, 0.94)

1.01 (0.19, 5.38)

0.40 (0.21, 0.76)

0.22 (0.13, 0.38)

0.79 (0.74, 0.84)

0.63 (0.47, 0.84)

0.75 (0.60, 0.94)

0.58 (0.41, 0.82)

0.64 (0.44, 0.93)

0.68 (0.45, 1.02)

0.48 (0.22, 1.06)

0.52 (0.32, 0.85)

1.10 (0.96, 1.26)

0.30 (0.17, 0.54)

0.49 (0.24, 1.01)

0.46 (0.25, 0.86)

ES (95% CI)

0.68 (0.42, 1.08)

0.29 (0.23, 0.36)

0.47 (0.20, 1.11)

0.64 (0.57, 0.72)

0.74 (0.51, 1.07)

0.97 (0.78, 1.21)

0.61 (0.45, 0.83)

0.55 (0.31, 0.99)

1.02 (0.88, 1.19)

0.94 (0.89, 1.00)

0.67 (0.55, 0.81)

0.90 (0.51, 1.59)

0.69 (0.63, 0.75)

0.33 (0.19, 0.57)

0.74 (0.58, 0.94)

1.01 (0.19, 5.38)

0.40 (0.21, 0.76)

0.22 (0.13, 0.38)

0.79 (0.74, 0.84)

0.63 (0.47, 0.84)

0.75 (0.60, 0.94)

0.58 (0.41, 0.82)

0.64 (0.44, 0.93)

0.68 (0.45, 1.02)

0.48 (0.22, 1.06)

0.52 (0.32, 0.85)

1.10 (0.96, 1.26)

0.30 (0.17, 0.54)

0.49 (0.24, 1.01)

0.46 (0.25, 0.86)

ES (95% CI)

0.68 (0.42, 1.08)

0.29 (0.23, 0.36)

0.47 (0.20, 1.11)

Favours intervention

1.1 .5 .75 1 2

9

Effectiveness: Sanitation interventions



Pradhan & Rawlings (2002)

Moraes et al (2003)

ID

Chavasse et al (1999)

Kolahi et al (2008)

Root (2001)

Study

0.52 (0.29, 0.96)

0.43 (0.07, 2.70)

0.31 (0.28, 0.34)

ES (95% CI)

0.78 (0.70, 0.87)

0.96 (0.75, 1.24)

0.32 (0.18, 0.57)

0.52 (0.29, 0.96)

0.43 (0.07, 2.70)

0.31 (0.28, 0.34)

ES (95% CI)

0.78 (0.70, 0.87)

0.96 (0.75, 1.24)

0.32 (0.18, 0.57)


10

Effectiveness: Hygiene interventions



Luby et al (2005)

Ahmed et al (1993)

Han & Hlaing (1989)

Haggerty et al (1994)

Bateman et al (1995)

Luby et al (2008)

Sircar et al (1987)

Pattanayak et al (2007)

Shahid et al (1996)

Wilson et al (1991)

Luby et al (2004)

Torun (1982)

Pinfold & Horan (1996)

Luby et al (2006)

Stanton et al (1988)

ID

Lee et al (1991)

Study

0.68 (0.60, 0.76)

0.47 (0.36, 0.61)

0.64 (0.61, 0.66)

0.75 (0.60, 0.93)

0.94 (0.87, 1.03)

0.27 (0.19, 0.38)

0.95 (0.69, 1.32)

0.92 (0.72, 1.17)

0.77 (0.68, 0.87)

0.44 (0.37, 0.53)

0.14 (0.03, 0.62)

0.71 (0.49, 1.04)

0.81 (0.75, 0.87)

0.61 (0.37, 1.00)

0.72 (0.47, 1.11)

0.78 (0.74, 0.83)

ES (95% CI)

0.67 (0.58, 0.77)

0.68 (0.60, 0.76)

0.47 (0.36, 0.61)

0.64 (0.61, 0.66)

0.75 (0.60, 0.93)

0.94 (0.87, 1.03)

0.27 (0.19, 0.38)

0.95 (0.69, 1.32)

0.92 (0.72, 1.17)

0.77 (0.68, 0.87)

0.44 (0.37, 0.53)

0.14 (0.03, 0.62)

0.71 (0.49, 1.04)

0.81 (0.75, 0.87)

0.61 (0.37, 1.00)

0.72 (0.47, 1.11)

0.78 (0.74, 0.83)

ES (95% CI)

0.67 (0.58, 0.77)


11

Heterogeneity – ‘high quality’

0

0.25

0.5

0.75

1

1.25

All studies(7 obs)

'Quality'(2 obs)

POU (3obs)

All studies(29 obs)

'Quality'(23 obs)

All studies(5 obs)

‘Quality’(3 obs)

All studies(16 obs)

‘Quality’(12 obs)

Soap(7 obs)

Water supply Water treatment Sanitation Hygiene

12

A closer look at water treatment

Effect 95% CI Num studies

Point of use 0.60 0.52 0.68 21

Source 0.85 0.63 1.15 2

No placebo/blinding 0.60 0.52 0.70 22

Placebo/blinded trials 0.75 0.56 1.01 6

Placebo/blinded trials excl. Luby et al. (2004, 2006) 0.90 0.65 1.25 4

Possible conflict of interest 0.51 0.36 0.73 7

No conflict of interest declared 0.69 0.60 0.78 19

13

4. Sustainability Water supply and sanitation: sustainability/scalability assessed

Water treatment and hygiene: replicability demonstrated; sustainability and scalability not=> only 5 follow-up studies assessing compliance + health impact over one

year after intervention completed

Most studies assess adoption/compliance with intervention => success / failure

Contextual factors identified, often through use of moderator (interaction variable) in analysis: e.g. age, carer’s education level, income, time.

Behavioural factors identified: individual preferences (e.g. taste) and agency (intra-household effects), intra-community ownership + interpersonal networks

14

Sustainability: quantitative

0

0.5

1

1.5

> 12 months(5 obs)

≤ 12 months(1 obs)

> 12 months(1 obs)


> 12 months(4 obs)


> 12 months(11 obs)


Water supply POU w ater treatment Source w ater treatment Total interventions

15

Sustainability: qualitative (water treatment) 3 follow-up studies of successful trials were conducted over one

year after the initial intervention ended:

Brown et al (2007): ceramic filter provision in Cambodia; 3 years later only 31% compliance

Iijima et al (2001): pasteurisation in Kenya; 4 years later only 30% compliance

Luby et al (2008): water disinfectant in Guatemala; compliance (repeated use) only 5%.

One study evaluated the reasons for low compliance of unsuccessful intervention: source water treatment (UV filtration) in rural Mexico (de Wilde et al 2008):

Community capacity to manage, physical faults or under-valuing of safe water by users were NOT found to be limiting the intervention’s effectiveness

Constraints (money & time) and availability of other sources, meant households chose more convenient water sources

16

No one single intervention for improving global access to water and sanitation for reducing diarrhoeal disease:

the ‘right’ solution is the one that fits the (social, economic, political) context

emphasise behavioural factors, particularly where these are of overriding importance to adoption (water quality + hygiene interventions)

5. Conclusions

17

5. Conclusions (cont’d)

Effectiveness: Water supply interventions least effective, excl household

connection Water treatment at point-of-use very effective, but concerns

about study quality (blinding) and conflict of interest Water treatment at source less effective but few high quality

studies Sanitation effective – more studies needed Hygiene interventions are effective (at least in short term) but

resource intensive Interventions substitutes (results not reported)

Evidence on sustainability + scalability of water treatment and hygiene interventions limited

Water and sanitation interventions for better child health: Evidence from a synthetic review Hugh...

Documents

Transcript of Water and sanitation interventions for better child health: Evidence from a synthetic review Hugh...