Social inequality in infant mortality: What explains variation across low and middle income countries?

Highlights

• One of the first comprehensive studies of social inequalities in infant mortality.

• Relative social inequalities in infant mortality were higher in wealthier LMICs.

• Absolute social inequalities in infant mortality were higher in poorer LMICs.

• Reducing teenage pregnancy may mitigate social inequalities in infant mortality.

Abstract

Growing work demonstrates social gradients in infant mortality within countries. However, few studies have compared the magnitude of these inequalities cross-nationally. Even fewer have assessed the determinants of social inequalities in infant mortality across countries. This study provides a comprehensive and comparative analysis of social inequalities in infant mortality in 53 low-and-middle-income countries (LMICs). We used the most recent nationally representative household samples (n = 874,207) collected through the Demographic Health Surveys (DHS) to calculate rates of infant mortality. The relative and absolute concentration indices were used to quantify social inequalities in infant mortality. Additionally, we used meta-regression analyses to examine whether levels of inequality in proximate determinants of infant mortality were associated with social inequalities in infant mortality across countries. Estimates of both the relative and the absolute concentration indices showed a substantial variation in social inequalities in infant mortality among LMICs. Meta-regression analyses showed that, across countries, the relative concentration of teenage pregnancy among poorer households was positively associated with the relative concentration of infant mortality among these groups (beta = 0.333, 95% CI = 0.115 0.551). Our results demonstrate that the concentration of infant deaths among socioeconomically disadvantaged households in the majority of LMICs remains an important health and social policy concern. The findings suggest that policies designed to reduce the concentration of teenage pregnancy among mothers in lower socioeconomic groups may mitigate social inequalities in infant mortality.

Introduction

Improving the health outcomes of children has been the central focus of many public health programs (Simon et al, 2001) in the world over the last three decades. To date, there have been several international goals set out to improve child health. The Declaration of Alma Ata (1978) aimed to reduce infant mortality rates (IMR) to less than 50 death per 1000 live-births through a global strategy for "Health for All" by the Year 2000 (World Health Organization, 1981). Subsequently, the 1990 World Summit for Children Programme of Action and the Programme of Action of the 1994 International Conference on Population and Development (ICPD) encouraged countries to reduce infant mortality. Another international effort targeting infant mortality is the fourth goal of the United Nations Millennium Development Goals (MDG 4). The MDG 4 is set to reduce IMRs between 1990 and 2015 by two thirds.

Despite the remarkable improvement in child health over the past three decades, infant mortality still remains a central issue in the global health agenda. There is extremely uneven progress towards reducing infant mortality across countries and regions (World Bank, 2012a, You et al., 2011), Furthermore, there is a growing body of global research demonstrating a social gradient in children's health outcome within countries: children belonging to lower compared to higher socioeconomic status (SES) households have a lower probability of surviving to their first birthday (Adler and Ostrove, 1999, Adler et al., 1994, Arntzen and Nybo Andersen, 2004, Bakketeig et al., 1993, Finch, 2003, Hobcraft et al., 1984, Hosseinpoor et al., 2006). The vast majority of these deaths are preventable and inequitable (Hosseinpoor et al., 2006, WHO/UNICEF, 2012, WHO/World Bank, 2002).

The monitoring of socioeconomic inequalities in child health within and among countries has an important role in gauging progress toward the commitments made by decision makers to reduce inequalities in infant mortality (Victora et al, 2003). However, measuring socioeconomic inequalities alone is not enough to secure sustainable changes. Identifying the factors explaining the concentration of infant mortality among children born into lower SES households is essential to implementing effective policies to redress these inequalities (Hosseinpoor et al., 2006, Victora et al., 2003).

Although inequalities in health have recently received substantial attention in the economics and public health literature (Costa-Font and Hernández-Quevedo, 2012, Gwatkin, 2000, Kawachi et al., 2002, Marmot and Wilkinson, 2006, O'Donnell et al., 2008, Wagstaff et al., 1991), few studies (Hosseinpoor et al., 2006, Monteiro et al., 2010, Pradhan and Arokiasamy, 2010, Vapattanawong et al., 2007, Wang, 2003, Zere et al., 2007) have measured socioeconomic inequalities in infant mortality using a summary measure such as the concentration index, which accounts for inequality across the entire socioeconomic distribution. Therefore, this study aimed to provide a comprehensive and comparative analysis of social inequality in infant mortality across 53 low-and-middle-income countries (LMICs) using the most recent nationally representative samples of live births collected through the Demographic Health Surveys (DHS). In addition, following the conceptual framework developed by Houweling and Kunst (2010) we used meta-regression to analyze whether inequalities in proximate risk factors for infant mortality were associated with the magnitude of social inequality in infant mortality across countries.