Inequality in access to improved drinking water sources and childhood diarrhoea in low- and middle-income countries

In addition to the conventional wisdom of categorizing countries based on nationally-averaged coverage in access to improved drinking water sources (IDWS), this study incorporated sub-national inequality into a novel categorisation framework. The association between access to IDWS and the incidence of childhood diarrhoea (ICD) was also quantified. Information from 1.63 million households obtained through nationally representative and cross-sectional demographic and health survey (DHS) and multiple indicator cluster survey (MICS) from 81 countries were analysed. Sub-national inequalities in the access to IDWS were measured using proportional variability (PV). Most studied countries with low coverage and high inequalities in accessing IDWS were from Sub-Saharan Africa (SSA). Wealth status of households showed a higher variability in the IDWS than the variability across locations. Significant negative associations between accessing IDWS and ICD were observed for regional models, except for SSA. This study adds knowledge towards understanding the state of sustainable development goal achievements in terms of accessing IDWS. The knowledge may be helpful in designing country-specific, achievable, short- and long-term strategies. The non-decisive relation between access to IDWS and ICD indicates the adoption of additional measures in the modelling mechanism.