Impact of Water, Sanitation and Hygiene Interventions on Growth, Non-diarrheal Morbidity and Mortality in Children Residing in Low- and Middle-income Countries: A Systematic Review.

OBJECTIVE: To evaluate the impact of water, sanitation and hygiene (WASH) interventions in children (age <18 y) on growth, non-diarrheal morbidity and mortality in children.
DESIGN: Systematic review of randomized controlled trials, non-randomized controlled trials and controlled before-after studies.
SETTING: Low- and middle-income countries. PARTICIPANTS: 41 trials with WASH intervention, incorporating data on 113055 children. INTERVENTION: Hygiene promotion and education (15 trials), water intervention (10 trials), sanitation improvement (7 trials), all three components of WASH (4 trials), combined water and sanitation (1 trial), and sanitation and hygiene (1 trial). OUTCOME MEASURES: (i) Anthropometry: weight, height, weight-for-height, mid-arm circumference; (ii) Prevalence of malnutrition; (iii) Non-diarrheal morbidity; and (iv) mortality.
RESULTS: There may be little or no effect of hygiene intervention on most anthropometric parameters (low- to very-low quality evidence). Hygiene intervention reduced the risk of developing Acute respiratory infections by 24% (RR 0.76; 95% CI 0.59, 0.98; moderate quality evidence), cough by 10% (RR 0.90; 95% CI 0.83, 0.97; moderate quality evidence), laboratory-confirmed influenza by 50% (RR 0.5; 95% CI 0.41, 0.62; very low quality evidence), fever by 13% (RR 0.87; 95% CI 0.74, 1.02; moderate quality evidence), and conjunctivitis by 51% (RR 0.49; 95% CI 0.45, 0.55; low quality evidence). There was low quality evidence to suggest no impact of hygiene intervention on mortality (RR 0.65; 95% CI 0.25, 1.7). Improvement in water supply and quality was associated with slightly higher weight-for-age Z-score (MD 0.03; 95% CI 0, 0.06; low quality evidence), but no significant impact on other anthropometric parameters or infectious morbidity (low to very low quality evidence). There was very low quality evidence to suggest reduction in mortality (RR 0.45; 95% CI 0.25, 0.81). Improvement in sanitation had a variable effect on the anthropometry and infectious morbidity. Combined water, sanitation and hygiene intervention improved height-for-age Z scores (MD 0.22; 95% CI 0.12, 0.32) and decreased the risk of stunting by 13% (RR 0.87; 95% CI 0.81, 0.94) (very low quality of evidence). There was no evidence of significant effect of combined WASH interventions on non-diarrheal morbidity (fever, respiratory infections, intestinal helminth infection and school absenteeism) (low- to very-low quality of evidence). Any WASH intervention (considered together) resulted in lower risk of underweight (RR 0.81; 95% CI 0.69, 0.96), stunting (RR 0.77; 95% CI 0.68, 0.86) and wasting (RR 0.12, 0.85) (low- to very-low quality of evidence).
CONCLUSIONS: Available evidence suggests that there may be little or no effect of WASH interventions on the anthropometric indices in children from low- and middle-income countries. There is low- to very-low quality of evidence to suggest decrease in prevalence of wasting, stunting and underweight. WASH interventions (especially hygiene intervention) were associated with lower risk of non-diarrheal morbidity (very low to moderate quality evidence). There was very low quality evidence to suggest some decrease to no change in mortality. These potential health benefits lend support to the ongoing efforts for provision of safe and adequate water supply, sanitation and hygiene.