Estimating national, demographic, and socioeconomic disparities in water insecurity experiences in low-income and middle-income countries in 2020–21: a cross-sectional, observational study using nationally representative survey data

Background: We are facing a global water crisis. However, because most water indicators assess physical availability or infrastructure in aggregate, knowing which sociodemographic groups experience water insecurity is difficult. We aimed to assess the prevalence of water insecurity across low-income and middle-income countries (LMICs) and examine how it varies by sociodemographic characteristics and exposure to life disruptions due to the COVID-19 pandemic across and within countries. Methods: In this observational study, we used Individual Water Insecurity Experiences (IWISE) scale data from a cross-sectional, nationally representative sample of individuals aged 15 years and older (defined as adults) in 31 LMICs. The IWISE scale range is 0–36, and water insecurity was defined as a score of 12 or higher. We used multivariable linear regression models to assess how individual-level experiences with water insecurity related to sociodemographic characteristics in each country, region, and the pooled sample. Findings: 45 555 individuals from 31 LMICs completed the IWISE module between Sept 4, 2020, and Feb 24, 2021, and were included in the 2020 Gallup World Poll (GWP) database; 45 365 individuals had sufficient data to estimate the prevalence of water insecurity. 42 918 individuals from 30 LMICs had sufficient data to assess sociodemographic characteristics associated with water insecurity, and 39 161 individuals in 29 countries had sufficient data to assess how IWISE scale scores covaried with life disruptions due to the COVID-19 pandemic. The overall prevalence of water insecurity in 2020 was 14·2%, ranging by region from 36·1% in the sub-Saharan Africa region to 9·1% in the Asia region, and by country from 63·9% in Cameroon to 3·6% in China. In the pooled model including sociodemographic and COVID-19 factors, difficulty getting by on household income (vs no difficulty getting by: β 2·76 [95% CI 2·45–3·07]), living in the outskirts of a city (vs living in a large city: 0·85 [0·29–1·41]), and being greatly affected by the COVID-19 pandemic (vs not being affected: 2·36 [1·96–2·77]) were strongly associated with higher IWISE scores. In country and regional models, the sociodemographic factors most consistently associated with higher IWISE scores were difficulty getting by on household income and life disruptions due to the COVID-19 pandemic, but the strength of these associations varied across countries and regions. Interpretation: Through extrapolation of these nationally representative data, we estimate that hundreds of millions of people had life-altering experiences with water insecurity globally in 2020, and that their sociodemographic characteristics vary by country and region. Additional individual-level measurements globally could help pinpoint the characteristics of those who are most water insecure, thereby guiding the development of context-specific policy and interventions that will best serve those most affected. Funding: Carnegie Corporation, Northwestern University, and USAID