Deaths rose among youth and young adults in high-income North America from 2011 to 2023.
Global mortality rates are decreasing but not among children, adolescents and young adults, according to study results published in The Lancet.
"The rapid growth in the world's aging population and evolving risk factors have ushered in a new era of global health challenges," Christopher J.L. Murray, MD, DPhil, director of the Institute for Health Metrics and Evaluation at the University of Washington School of Medicine, said in a press release.
He added the data are "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."
Life expectancy and rising mortality have been major health issues in the U.S. in recent decades, with the country seeing its life expectancy stall, falling behind other comparable nations.
In the Global Burden of Disease 2023 study, Murray and colleagues assessed years lived with disability, years lived with disability and disability-adjusted life-years (DALYs) for 375 diseases and injuries and 88 risk factors across 204 countries and territories from 1990 to 2023.
The researchers reported that the 2023 global age-standardized mortality rate declined by 67% since 1950 -- with all countries and territories experiencing declines -- while the age-standardized DALY rate fell by 36% from 1990 to 2023 and by 12.6% from 2010 to 2023.
Among adolescents and young adults, the largest increases in death occurred among those aged 20 to 39 years in high-income North America from 2011 to 2023, "mainly due to suicide, drug overdose and high quantities of alcohol," the release said.
Deaths during 2011 to 2023 also increased among those aged 5 to 19 years in high-income North America, Eastern Europe and the Caribbean.
Infant deaths declined more than any other age group globally over the study period.
Global life expectancy in 2023 was 71.5 years and 76.3 years for men and women, respectively, marking returns to pre-COVID-19-pandemic levels. This is more than 20 years higher vs. life expectancy in 1950, according to the release.
The DALY rates for communicable, maternal, neonatal and nutritional diseases (CMNN) fell by nearly 26% over the study period, which the release noted was driven "by rates for diarrheal diseases being cut in half, a 43% decrease in rates for HIV/AIDS and a 42% drop for tuberculosis."
The injury-related DALY rate declined by 15.6% from 2010 to 2023, with the burden of injuries highest in males, especially youth and young adults aged 10 to 24 years.
Murray and colleagues reported that nearly half (46%) of the global mortality and morbidity in 2023 was attributable to the 88 modifiable risk factors.
Among the risk factors with the highest proportion of health loss were systolic BP, particulate matter pollution, smoking, high fasting plasma glucose, lead exposure, low birthweight and short gestation, high BMI and high LDL cholesterol, according to the release.
The researchers pointed out the leading causes of death in the last several years shifted from infectious to non-communicable diseases. Specifically, COVID-19 fell from the top cause of death in 2021 to 20th in 2023.
Ischemic stroke became the leading cause of death in 2023, followed by chronic obstructive pulmonary disease, lower respiratory infections and neonatal disorders.
But the rates of death from ischemic stroke, as well as diseases like stomach cancer, stroke and measles, declined from 1990 to 2023.
During that period, the rates of death from HIV/AIDs, diabetes, Alzheimer's disease and chronic kidney disease rose.
Occurrences of mental health disorders rose substantially during the study period, with anxiety disorders and depressive disorders increasing by 63% and 26%, respectively.
Murray and colleagues found that neonatal disorders and lower respiratory infections remain the top causes of communicable, maternal, neonatal, and nutritional diseases, though both have declined in recent years.
"With focused efforts on prevention, risk mitigation and more robust health systems, substantial strides can be made towards improving population health and achieving long-term sustainable development targets," the researchers wrote.