Neonatal, postneonatal, childhood, and under-5 mortality for 187 countries, 1970–2010: a systematic analysis of progress towards Millennium Development Goal 4

Abstract

Mortality in children younger than 5 years is falling in every region of the world, dropping from 11.9 million deaths in 1990 to 7.7 million deaths in 2010, according to research by IHME. These figures represent a 35% reduction in under-5 mortality within 10 years, a rate of decline that was faster than expected. The study, Neonatal, postneonatal, childhood, and under-5 mortality for 187 countries, 1970-2010: a systematic analysis of progress towards Millennium Development Goal 4,  the first to use Gaussian progress regression to estimate child mortality, suggests that children are doing better today than at any time in recent history, especially in the first month of life.  The work was done in collaboration with scientists at the University of Queensland.

Research findings

The researchers found substantially lower estimates of child mortality than previous studies. Specifically, they found that the 7.7 million deaths in 2010 of children under 5 years comprise 3.1 million neonatal deaths, 2.3 million postneonatal deaths, and 2.3 million deaths in children aged 1 to 4 years. The majority of deaths in children younger than 5 years occurs in sub-Saharan Africa (49.6%) and South Asia (33.0%), with less than 1.0% of deaths occurring in high-income countries.  Nevertheless, in 13 regions of the world, including all regions of sub-Saharan Africa, there is evidence of accelerating declines. Within sub-Saharan Africa, rates of decline have sped up by at least a full percentage point over the past decade compared to the previous decade in 13 countries, including Angola, the Democratic Republic of the Congo, and Kenya.

As a result, 31 developing countries are on pace to meet Millennium Development Goal 4 (MDG 4) of reducing child deaths by 66% between 1990 and 2015. This includes countries such as Brazil, Mexico, Malaysia, and Egypt.  In 1990, 12 countries had an under-5 mortality rate of more than 200 deaths per 1,000 live births. Today, no country has an under-5 mortality rate that high, according to IHME estimates.

In Ethiopia, the under-5 mortality rate in 1990 was 202 per 1,000 live births, one of the highest rates in the world. By 2010, that rate has dropped by half to 101 per 1,000. Even countries with low numbers of child deaths have continued to see mortality declines. Singapore had a child mortality rate of eight per 1,000 live births in 1990, but by 2010, that rate had dropped to two, the lowest in the world.

In high-income countries, which make up less than 1% of all child deaths, stark differences remain. The United States, for example, ranks 42nd in the world for its 2010 under-5 mortality rate, lower than most of Europe, including countries with far fewer resources, such as Estonia, Croatia, and Hungary.

Analytical approach

Researchers compiled a database of 16,174 measurements of mortality in children younger than 5 years for 187 countries from 1970 to 2009, and used data from all available sources, including vital registration systems, summary birth histories in censuses and surveys, and complete birth histories. Gaussian process regressions were used to generate estimates of the probability of death between birth and 5 years. Neonatal, postneonatal, and childhood mortality was estimated from mortality in children younger than 5 years with 1,760 measurements from vital registration systems and complete birth histories that contained specific information about neonatal and postneonatal mortality.

Research objective

Previous research has highlighted that less than a quarter of countries are on track to achieve MDG 4, which calls for a two-thirds reduction in mortality in children younger than 5 years between 1990 and 2015. Given policy changes and investments that have occurred in the last 10 years, the researchers aimed to assess the extent to which countries have achieved the MDG 4 target. This research is part of ongoing work by IHME to better measure global health by generating systematic estimates of demographics, including mortality.

Recommendations for future work

The finding that many low-income countries are experiencing an accelerated decline in child mortality does not take into account the possible reasons for this finding, including increased coverage of health interventions, such as immunization, insecticide-treated bed nets, prevention of mother-to-child HIV, and antiretroviral drug administration. It is crucial for future research to conduct careful country case studies to help explain this finding. Researchers should also take the next step to relate levels and trends in child mortality to changes in the key drivers of child mortality, including income per capita and level of maternal education, to better understand where country performance has been better than expected. Finally, there is evidence of a slowing decline in mortality in some countries, including the US, UK, New Zealand, and South Korea, showing rates that are slower than expected. These cases merit further scrutiny to identify factors responsible for slowdowns in progress that might be amenable to intervention.