【要旨／ハイライト】
There are 3.5 billion people living without safe toilets worldwide, who often have no choice but to use unreliable, inadequate toilets or engage in open defecation. The negative impacts of lacking appropriate toilets are particularly noticeable in infants and children, including diseases, stunted growth, chronic malnutrition, and in some cases, death. However, evidence showing these negative effects based on nationally representative data is lacking and thus a thorough analysis is needed. Therefore, in this study, we explore how the extent of toilet coverage is associated with under-five mortality in Cambodia. We use the censuses conducted in 2008 and 2019 in Cambodia to create village-level panel data that include information on the extent of toilet coverage and what kinds of toilets are used. We use the constructed village-level panel data to perform an instrumental variable regression analysis aimed at elucidating the association of toilet coverage with under-five mortality at the village level. We find that increased toilet coverage in a given village is associated with reduced under-five mortality in that village. Increased coverage of improved toilets in particular is associated with lower under-five mortality, suggesting that cleaner toilets save young children’s lives. This finding is useful to policymakers in developing countries facing challenges regarding the widespread use of toilets.