Impact of a sanitation intervention on quality of life and mental wellbeing in low-income urban neighbourhoods of Maputo, Mozambique

Objectives: Toilet users often report valuing privacy and safety more highly than reduced disease, but effects of urban sanitation interventions on such outcomes have never been assessed quantitatively. In this study, we evaluate the impact of a shared sanitation intervention on quality of life (QoL) and mental wellbeing. Design: We interviewed individuals living in intervention and control clusters of a recent non-randomised controlled trial, and used generalised linear mixed regression models to make an observational comparison of outcomes. Setting: low-income unsewered areas of Maputo City, Mozambique Participants: We interviewed 424 participants, 222 from the prior trial's intervention group, and 202 from the control group. Interventions: The control group used low-quality pit latrines. The intervention group received high-quality shared toilets, contributing 10-15% of capital cost. Outcomes: Our primary outcome was the sanitation-related quality of life (SanQoL) index, which applies respondent-derived weights to combine toilet users' perceptions of sanitation-related disgust, privacy, safety, health, and shame. Secondary outcomes were the WHO-5 mental wellbeing index and a sanitation visual analogue scale. Results: The intervention group experienced a 1.6 standard deviation gain in SanQoL compared to the control group. This adjusted SanQoL gain was 0.34 (95% CI: 0.29-0.38) on a 0-1 scale with control mean 0.49. Effect sizes were largest for safety and privacy attributes. Intervention respondents also experienced a 0.2 standard deviation gain in mental wellbeing. The adjusted gain was 6.2 (95% CI: 0.3-12.2) on a 0-100 scale with control mean 54.4. Conclusions: Quality of life outcomes highly valued by toilet users and can be improved by sanitation interventions. Such outcomes should be measured in future sanitation trials, to help identify interventions which most improve people's lives. Since SanQoL weights are derived from respondent valuation, the measure can also be used in economic evaluation.