Trends in socioeconomic inequalities in stunting prevalence in Latin America and the Caribbean countries: differences between quintiles and deciles

BACKGROUND: With the adoption of the Sustainable Development Goals (SDGs), there is a renewed commitment of tackling the varied challenges of undernutrition, particularly stunting (SDG 2.2). Health equity is also a priority in the SDG agenda and there is an urgent need for disaggregated analyses to identify disadvantaged subgroups. We compared time trends in socioeconomic inequalities obtained through stratification by wealth quintiles and deciles for stunting prevalence. METHODS: We used 37 representative Demographic and Health Surveys and Multiple Indicator Cluster surveys from nine Latin American and Caribbean (LAC) countries conducted between 1996 and 2016. Stunting in children under-5 years was assessed according to the 2006 WHO Child Growth Standards and stratified by wealth quintiles and deciles. Within-country socioeconomic inequalities were measured through concentration index (CIX) and slope index of inequality (SII). We used variance-weighted least squares regression to estimate annual changes. RESULTS: Eight out of nine countries showed a statistical evidence of reduction in stunting prevalence over time. Differences between extreme deciles were larger than between quintiles in most of countries and at every point in time. However, when using summary measures of inequality, there were no differences in the estimates of SII with the use of deciles and quintiles. In absolute terms, there was a reduction in socioeconomic inequalities in Peru, Honduras, Dominican Republic, Belize, Suriname and Colombia. In relative terms, there was an increase in socioeconomic inequalities in Peru, Bolivia, Haiti, Honduras and Guatemala. CONCLUSIONS: LAC countries have made substantial progress in terms of reducing stunting,. Nevertheless, renewed actions are needed to improve equity. Particularly in those countries were absolute and relative inequalities did not change over time such Bolivia and Guatemala. Finer breakdowns in wealth distribution are expected to elucidate more differences between subgroups; however, this approach is relevant to cast light on those subgroups that are still lagging behind within populations and inform equity-oriented health programs and practices.