Water Matters More: Unequal Effects of Water and Sanitation on Child Growth in Mozambique.

Background: Child stunting and wasting persist at alarmingly high rates in Mozambique, yet little is known about whether the improved sources of water and sanitation affect these outcomes differently. This study aims to disentangle the distinct contributions of improved water sources and sanitation facilities to child stunting and wasting at the national level, addressing a critical evidence gap in the WASH-nutrition literature in Mozambique. Methods: Using data from 3690 children under five in the 2022-2023 Mozambique Demographic and Health Survey, we applied stepwise logistic regression models to estimate the independent and combined associations of improved drinking water and sanitation facilities with child stunting and wasting, adjusting for child-, household-, and region-level factors. Results: Improved water access was significantly associated with a lower risk of stunting (odds ratio = 0.80, 95% CI: 0.67-0.94, p < 0.01), while sanitation showed only weak and inconsistent associations with stunting. In the fully adjusted model, neither improved water nor sanitation was associated with wasting. Wealth, gender, religion, and region were also significant predictors of stunting as well as wasting. Conclusions: These findings indicate that WASH components protect against child malnutrition through different pathways, with water being more protective against chronic undernutrition and sanitation less clearly linked to acute malnutrition. Broader socioeconomic and cultural factors-such as wealth, religion, and geography-play critical roles, highlighting the need for integrated, context-specific interventions.