Working-age US adults are dying at far higher rates than their peers from high-income countries, even surpassing death rates in Central and Eastern European countries, and midlife mortality rates in the UK are not great either. A new study has examined what’s caused this rise in the death rates of these two cultural superpowers.

Life expectancy started to rise around 1840 at a pace of almost 2.5 years per decade and has continued to the present day. A 2021 study calculated that if the current pace continues, most children born this millennium will live to celebrate their 100th birthday. However, new research by the Leverhulme Center for Demographic Science (LCDS) at the University of Oxford and Princeton University has revealed some troubling trends for those in midlife, particularly in the US and the UK.

“Over the past three decades, midlife mortality in the US has worsened significantly compared to other high-income countries, and for the younger 20- to 44-year-old age group, in 2019, it even surpassed midlife mortality rates for Central and Eastern European countries,” said Katarzyna Doniec, the study’s corresponding author. “This is surprising, given that not so long ago, some of these countries experienced high levels of working-age mortality, resulting from the post-socialist [economic] crisis of the 1990s.”

The study demonstrates that most countries have experienced declines in all-cause mortality over the three decades to 2019. The notable exception is the United States, whose divergence from comparable high-income countries in age-standardized mortality rates of 25- to 64-year-olds has accelerated over time. Strikingly, for US females aged 25 to 44, all-cause mortality rates were higher in 2019 than in 1990. The country’s higher mortality was especially noticeable when it came to preventable deaths: homicides, deaths from transport accidents, and so-called ‘deaths of despair’ related to suicide and alcohol and drug use.