The reduction in international aid is in danger of reversing decades of efforts to enhance life expectancy in emerging economies across the world a new report has warned.

The latest edition of the Global Burden of Disease (GBD) study presented yesterday to the World Health Summit in Berlin by the Institute for Health Metrics and Evaluation (IHME) found global mortality rates are falling but not among youths and young adults.

Additionally, non-communicable diseases (NCDs) now account for nearly two-thirds of the world’s total mortality and morbidity, with ischemic heart disease, stroke, and diabetes leading the globe. Researchers also estimate that nearly half of all death and disability could be prevented by modifying some of the leading risk factors, such as reducing high levels of blood sugar and high body mass index (BMI).

“The rapid growth in the world’s aging population and evolving risk factors have ushered in a new era of global health challenges,” said Dr. Christopher Murray, director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington School of Medicine. “The evidence presented in the Global Burden of Disease study is a wake-up call, urging government and health care leaders to respond swiftly and strategically to the disturbing trends that are reshaping public health needs.”

Murray’s team at IHME and its GBD Collaborator Network of 16,500 scientists and researchers collected and analysed data and produced estimates for 375 diseases and injuries and 88 risk factors by age and sex globally, regionally, and nationally for 204 countries and territories and 660 subnational locations from 1990 to 2023, making the GBD the most comprehensive research quantifying health loss.

Despite population growth and aging, the 2023 global age-standardised mortality rate declined 67% since 1950, and all countries and territories marked declines. Global life expectancy returned to pre-pandemic levels at 76.3 years for females and 71.5 years for males, which is more than 20 years higher compared to 1950. Despite this progress, stark geographic differences remain, with life expectancy ranging from as high as 83 years in high-income regions to as low as 62 years in sub-Saharan Africa.

Among adolescents and young adults, the largest increase in deaths was registered among those aged 20 to 39 in high-income North America from 2011 to 2023, mainly due to suicide, drug overdose, and high quantities of alcohol. During the same period, deaths in the 5–19-year age group increased in Eastern Europe, high-income North America, and the Caribbean.

Over the entire study period, the number of infant deaths declined more than for any other age group. From 2011 to 2023, East Asia recorded the largest decrease of 68% in the mortality rate for the under-5 age group due to better nutrition, vaccines, and stronger health systems.

The report added causes of death are shifting from infectious to non-communicable diseases (NCDs), creating new global health challenges, particularly for low-income countries. After standing as the leading cause of death in 2021, COVID-19 plunged to the 20th place in 2023, putting ischemic heart disease and stroke back at the top, followed by chronic obstructive pulmonary disease, lower respiratory infections, and neonatal disorders.

Since 1990, mortality rates for ischemic heart disease and stroke have declined, and so have diarrheal diseases, tuberculosis, stomach cancer, and measles. Conversely, during the same period the death rate increased for diabetes, chronic kidney disease, Alzheimer’s disease, and HIV/AIDS.

While the global mean age at death increased from 46.4 in 1990 to 62.9 years in 2023, geographic inequities were profound. The highest mean age of death was recorded in the high-income super-region, with females reaching 80.5 years and males at 74.4 years. The lowest mean age of death was in sub-Saharan Africa, with females at 37.1 years and males at 34.8 years.

Climate-sensitive risks, such as air pollution and heat, continue to have a more significant impact on global health. The DALY rates for the second-leading risk, particulate matter pollution, were highest at the super-region level in South Asia, sub-Saharan Africa, and North Africa and the Middle East. High temperatures are also exacerbating vulnerabilities in that same region, particularly the Sahel, by compounding the effects of drought, food insecurity, and displacement.

Mental health disorders rose steeply, with anxiety disorders increasing by 63% and depressive disorders by 26%. In addition, sexual abuse and intimate partner violence were identified as preventable contributors to depression, anxiety, and other health consequences.

The GBD 2023 study highlighted the urgent need for policymakers to expand health priorities beyond reducing child mortality to include adolescents and young adults, particularly in areas with higher rates of mortality than previously known.

Decades of work to close the gap in low-income regions with persistent health inequities are in danger of unravelling due to the recent cuts to international aid. These countries rely on global health funding for life-saving primary care, medicine, and vaccines. Without it, the gap is sure to widen,” explained Emmanuela Gakidou, senior author and professor at IHME.

Among adolescents and young adults, the largest increase in deaths was registered among those aged 20 to 39 in high-income North America from 2011 to 2023, mainly due to suicide, drug overdose, and high quantities of alcohol. During the same period, deaths in the 5–19-year age group increased in Eastern Europe, high-income North America, and the Caribbean.