Worldwide, regional and national estimates of cause of death and neonatal outcomes

Worldwide, Regional and National Estimates

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CAUSE OF DEATH

This work focuses on improving the models from which cause of death estimates for newborns are derived. This project is undertaken in partnership with, and under the umbrella of, CHERG/MCEE, and in close collaboration with the WHO Department of Health Statistics and Information Systems and staff at John Hopkins who are responsible for estimating causes of child deaths in the post-neonatal period. Since the early 2000s, the team has been working on producing cause of death estimates with time trends at national, regional and global levels for 194 countries, most recently 2000-2018, as well as subnational level estimates for India.

Key publications:

 

For more information visit the John Hopkins Bloomberg School of Public Health

LOW BIRTHWEIGHT

Global nutrition targets set at the World Health Assembly in 2012 include an ambitious 30% reduction in low birthweight prevalence by 2025. Estimates to track progress towards this target are lacking and this analysis aimed to assist in setting a baseline against which to assess progress towards the achievement of the World Health Assembly targets. This project estimated worldwide, regional and national low birthweight prevalence and numbers for 148 countries in 2015, including trends from 2000.

All available low birthweight input data for livebirths for 2000-2016 were sought. Population-based national or nationally representative datasets were considered for inclusion if they contained information on birthweight or low birthweight prevalence for livebirths. A new method for survey adjustment was developed and used. For 57 countries with higher quality time-series data, country-reported trends in birthweight data were smoothed by use of B-spline regression. For all other countries, low birthweight prevalence and trends were estimated by use of a restricted maximum likelihood approach with country-level random effects. Uncertainty ranges were obtained through bootstrapping. Results were summed at the regional and worldwide level.

Key findings:

  • 1447 country-years of birthweight data (281 million births) for 148 countries of 195 UN member states (47 countries had no data meeting inclusion criteria) were included in the study
  • In 2015, the estimated worldwide prevalence of low birthweight was 14·6% (uncertainty range 12·4-17·1) compared with 17·5% (14·1-21·3) in 2000 (average annual reduction rate 1·23%)
  • In 2015, an estimated 20·5 million (17·4-24·0 million) livebirths were low birthweight, 91% from low-and-middle income countries, mainly southern Asia (48%) and sub-Saharan Africa (24%).

Publications: Estimates were published in July 2019: https://www.ncbi.nlm.nih.gov/pubmed/31103470.

STILLBIRTH

The Every Newborn Action Plan (ENAP) targets national stillbirth rates of 12 or fewer stillbirths per 1000 births by 2030. This project estimated worldwide, regional and national stillbirth rates and numbers for 195 countries in 2015, including trends from 2000.

SBR data meeting pre-specified inclusion criteria was collated from national routine or registration systems, nationally representative surveys, and other data sources identified through a systematic review, web-based searches, and consultation with stillbirth experts. Stillbirth rates (≥28 weeks’ gestation) for 195 countries were modelled with restricted maximum likelihood estimation with country-level random effects. Uncertainty ranges were obtained through a bootstrap approach.

Key findings:

  • Data from 157 countries met the inclusion criteria, a 90% increase from 2009 estimates
  • In 2015, the estimated average global SBR was 18·4 per 1000 births, down from 24·7 in 2000 (25·5% reduction)
  • In 2015, an estimated 2·6 million (uncertainty range 2·4-3·0 million) babies were stillborn, giving a 19% decline in numbers since 2000 with the slowest progress in sub-Saharan Africa
  • The vast majority, 98%, of all stillbirths occur in low-income and middle-income countries; 77% in south Asia and sub-Saharan Africa.

Key publications:

PRETERM BIRTH

Preterm birth is the second largest direct cause of child deaths in children younger than 5 years. Yet, data regarding preterm birth (<37 completed weeks of gestation) are not routinely collected by UN agencies, and no systematic country estimates nor time trend analyses have been done. This project estimated worldwide, regional, and national estimates of preterm birth rates for 184 countries in 2010 with time trends for selected countries.

Various data sources were assessed according to pre-specified inclusion criteria. National Registries, Reproductive Health Surveys, and studies identified through systematic searches and unpublished data were included. 55 countries submitted additional data during a country consultation process. For 13 countries with adequate quality and quantity of data, preterm birth rates were estimated using country-level loess regression for 2010. For 171 countries, two regional multilevel statistical models were developed to estimate preterm birth rates for 2010. Time trends from 1990 to 2010 were estimated for 65 countries with reliable time trend data and > 10,000 livebirths per year.

Key findings:

  • In 2010, an estimated 14·9 million babies (uncertainty range 12·3-18·1 million) were born preterm
  • This equates to 11·1% of all livebirths worldwide, ranging from about 5% in several European countries to 18% in some African countries
  • More than 60% of preterm babies were born in south Asia and sub-Saharan Africa
  • High-income countries also had high rates and the USA is one of the ten countries with the highest numbers of preterm births
  • Of the 65 countries with estimated time trends, only three (Croatia, Ecuador, and Estonia), had reduced preterm birth rates 1990-2010.

Publications: Estimates were published in 2013: https://www.ncbi.nlm.nih.gov/pubmed/22682464.

GLOBAL BURDEN OF DISEASE DUE TO NEONATAL MORTALITY

This project aimed to estimate the global burden of disease resulting from neonatal mortality and morbidity, including preterm birth, retinopathy of prematurity, neonatal encephalopathy, neonatal jaundice, and neonatal infections.

For five conditions (preterm birth, retinopathy of prematurity, intrapartum-related conditions, neonatal infections, and neonatal jaundice), a standard three-step compartmental model was applied to estimate— by region, for 2010—the numbers of (i) affected births by sex, (ii) postneonatal survivors, and (iii) impaired postneonatal survivors. For conditions included in GBD2010 analyses (preterm birth and intrapartum-related conditions), impairment at all ages was estimated, and disability weights were applied to estimate years lived with disability (YLD) and summed with years of life lost (YLL) to calculate disability-adjusted life years (DALYs). These were the first systematic estimates of impairment after neonatal morbidity.

Key findings:

  • Neonatal conditions (preterm birth, intrapartum-related, neonatal sepsis and ‘other neonatal’ were responsible for 202 million DALYs or 8.1% of total annual DALYs in 2010
  • Of those DALYs, mortality contributed 95%
  • Between 1990 and 2010, impairment following neonatal conditions remained stable globally

Publications: A supplement of the findings was published in 2013: https://www.nature.com/collections/bnlnvsbflm.

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