Elsevier

The Lancet

Volume 377, Issue 9772, 2–8 April 2011, Pages 1162-1174
The Lancet

Articles
50-year mortality trends in children and young people: a study of 50 low-income, middle-income, and high-income countries

https://doi.org/10.1016/S0140-6736(11)60106-2Get rights and content

Summary

Background

Global attention has focused on mortality in children younger than 5 years. We analysed global mortality data for people aged 1–24 years across a 50-year period.

Methods

The WHO mortality database was used to obtain mortality data from 1955 to 2004, by age-group (1–4, 5–9, 10–14, 15–19, and 20–24 years) and stratified by sex. To analyse change in mortality, we calculated mortality rates averaged over three 5-year periods (1955–59, 1978–82, and 2000–04) to investigate trends in deaths caused by communicable and non-communicable diseases and injury.

Findings

Data were available for 50 countries (ten high income, 22 middle income, eight low income, seven very low income, and three unclassified), grouped as Organisation for Economic Co-operation and Development (OECD) countries, Central and South American countries, eastern European countries and ex-Soviet states, and other countries. In 1955, mortality was highest in the 1–4-year age-group. Across the study period, all-cause mortality reduced by 85–93% in children aged 1–4 years, 80–87% in children aged 5–9 years, and 68–78% in young people aged 10–14 years in OECD, Central and South American, and other countries. Smaller declines (41–48%) were recorded in young men (15–24 years), and by 2000–04, mortality in this group was two-to-three times higher than that in young boys (1–4 years). Mortality in young women (15–24 years) was equal to that of young girls (1–4 years) from 2000 onwards. Substantial declines in death caused by communicable diseases were seen in all age-groups and regions, although communicable and non-communicable diseases remained the main causes of death in children (1–9 years) and young women (10–24 years). Injury was the dominant cause of death in young men (10–24 years) in all regions by the late 1970s.

Interpretation

Adolescents and young adults have benefited from the epidemiological transition less than children have, with a reversal of traditional mortality patterns over the past 50 years. Future global health targets should include a focus on the health problems of people aged 10–24 years.

Funding

None.

Introduction

Global mortality trends in children and young people have been little studied, even though more than two-fifths of the world's population is aged 5–24 years. A strong international focus on reduction of mortality in children younger than 5 years (Millennium Development Goal 4)1 has reduced early childhood mortality by 35% since 1990,1, 2, 3 resulting in increased population sizes in later childhood (age >5 years) and adolescence. By comparison, mortality in later childhood and adolescence has been neglected, with the assumption that this period is the healthiest time of life.4 However, during the past 50 years, global social, economic, and political changes have adversely affected patterns of health and disease in adolescents and young adults.5

In the 2007 World Development Report,6 the World Bank concluded that adolescent health has substantial long-term effects on development and deployment of social and economic capital. Yet international data on mortality in children aged 5 years and older and young people are largely limited to cross-sectional data,5, 7 or inclusion within studies of adult mortality.8 In a systematic review done on Jan 17, 2011, we did not identify any longitudinal studies of global mortality in people aged 5–24 years. In the past 40–50 years, mortality from transport injuries, suicide, and homicide has risen in adolescents and young adults in high-income countries.5, 9, 10, 11, 12 Mortality in young people aged 15–24 years in the UK has exceeded that in children aged 1–4 years since the 1970s, a reversal of the traditional understanding of mortality in children and youth.10

Key messages

  • In 2000–04, mortality in people aged 15–24 years was higher than that in children aged 1–4 years in most countries studied, with the exception of some very low-income countries. Mortality in young men (15–24 years) was two-to-three times higher than that in boys (1–4 years).

  • Mortality in children aged 1–9 years declined by 80–93% in the 50 years up to 2004, due largely to steep declines in mortality from communicable diseases.

  • Improvements in mortality in young people aged 15–24 years were half that in children, due largely to static or rising injury-related mortality, particularly in young men.

  • Violence and suicide became increasingly important causes of death in young people in the second half of the 20th century, together making up a quarter to a third of mortality in young men aged 10–24 years in all regions by 2000–04.

  • The changing patterns of mortality suggest that future global health targets should have an increased emphasis on the health of adolescents and young adults.

A scarcity of data disaggregated by age has been a barrier to understanding mortality in people aged 5–24 years because these people are typically included in age-groups of 0–14 or 15–44 years. The WHO mortality database now collates historical registration data disaggregated by age. We used these data to examine international mortality trends in mortality from communicable and non-communicable diseases and injuries in children and young people during the 50 years from 1955 to 2004. We limited our study to people aged 1–24 years because infant mortality has already been extensively studied.

Section snippets

Study design

The WHO mortality database records numbers and causes of death (International Classification of Diseases 7–10) registered by WHO member states from 1950. We accessed the WHO mortality database on March 26, 2010, and obtained data aggregated in the age-groups of 1–4, 5–9, 10–14, 15–19, and 20–24 years, stratified by sex. We used a modified global burden of disease classification of causes of death13 (panel 1).

Few countries had contiguous data from 1950 onwards and data varied in completeness

Results

50 countries conformed to the eligibility criteria, and 95% of the country datasets for each year had at least 80% completeness. Of the 21 OECD countries, ten were high income and 11 were middle income. The remaining 29 countries were middle, low, or very low income or unclassified, of which 15 were from eastern Europe (including ex-Soviet states in Asia), ten were from Central and South America, and four from disparate regions (other countries) were small nations that have undergone very rapid

Discussion

This report presents a unique international overview of mortality trends in children after infancy, adolescents, and young adults in 50 countries of high, middle, and low income between the mid-20th century and the first years of the 21st century (panel 2). Overall mortality declined substantially between 1955 and 2004 in children and young people aged 1–14 years, and young women (15–24 years), but improvement in mortality was much lower in young men (15–24 years).

In the 1950s, mortality in

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