Interventions to improve sanitation for preventing diarrhoea.

Area of Science:

• Public Health
• Environmental Health
• Infectious Disease Epidemiology

Background:

• Diarrhoea is a significant global health issue, especially impacting children under five in low- and middle-income countries (LMICs).
• Faecal-oral transmission of infectious agents highlights the critical role of sanitation in disease prevention.

Purpose of the Study:

• To evaluate the effectiveness of sanitation interventions in preventing diarrhoeal disease.
• To assess interventions implemented alone or combined with other Water, Sanitation, and Hygiene (WASH) measures.

Main Methods:

• Systematic review and meta-analysis of randomized controlled trials (RCTs), quasi-RCTs, non-randomized controlled trials (NRCTs), controlled before-and-after studies (CBAs), and matched cohort studies.
• Searched multiple databases including Cochrane, MEDLINE, Embase, LILACS, and Chinese databases up to February 2022.
• Assessed risk of bias and certainty of evidence using the GRADE approach.

Main Results:

• Fifty-one studies involving 238,535 participants were included. Pooled analysis of all sanitation interventions showed a reduction in diarrhoea prevalence (RR 0.74, 95% CI 0.67 to 0.82).
• Providing access to sanitation facilities showed potential benefits (low-certainty evidence), while improving existing facilities also demonstrated protective effects (low-certainty evidence).
• Behaviour change messaging interventions showed moderate-certainty evidence of reducing diarrhoea prevalence (RR 0.82, 95% CI 0.69 to 0.98).

Conclusions:

• Sanitation interventions are effective in preventing diarrhoea across all age groups, particularly in LMICs.
• Effectiveness varies by intervention type and context, indicating a need for further research.
• While protective against dysentery and persistent diarrhoea, evidence for impact on clinic visits or mortality was limited.