UTMB researchers delve into troubling trends in US life expectancy

A new study published in the peer-reviewed journal Proceedings of the National Academy of Sciences (PNAS) reveals that U.S. life expectancy was already in crisis long before the COVID-19 pandemic and continues to face alarming threats from shifting patterns in chronic disease and emerging cancers.

Research by The University of Texas Medical Branch (UTMB), funded by a grant from the National Institutes of Health's National Institute on Aging (NIA), examined why life expectancy that consistently rose for more than a century stalled around 2010, defying expectations of steady improvement seen in most high-income countries.

Dr. Neil Mehta, a demographer, epidemiologist, and UTMB faculty member, served as senior author of the study. He and his team analyzed age-specific death rates across both birth cohorts and time periods, creating one of the most comprehensive pictures to date of mortality trends in the United States.

"We looked at mortality patterns in granular detail over many decades of birth cohorts creating a more complete picture on death rate changes than has been shown before," Mehta said.

Their findings show that stagnating life expectancy is not the result of a single cause but a complex convergence of rising chronic disease, shifting behavioral risks, and increases in certain cancers among younger adults.

"We wanted to understand why, at a time of major advances in medical care, Americans were no longer seeing gains in longevity," Mehta said.

The study identifies cardiovascular disease as one of the largest contributors to the nation's stalled life expectancy, despite dramatic progress in treatment and prevention over recent decades. The researchers also point to emerging increases in cancer, including colorectal cancer in specific birth cohorts, as warning signs that younger generations may face worsening health outcomes in the years ahead.

"This is a call to action," Mehta noted. "We are saving more lives through better medicine, but more people are getting sick, and that disconnect is driving these troubling trends."

The research shows that these trends are broad-based.

"This life expectancy stagnation is not attributable to a single birth cohort, and it is not attributable to a single age group," Mehta said. "It's really across the whole life course, which is very concerning."

Mehta said the cohorts born after 1970 looked particularly bad, especially in relation to cancer mortality and some heart disease mortality.

"They didn't look good at all, which would suggest that as they age, they are going to contribute negatively to life expectancy growth," Mehta said.

Leah Abrams, assistant professor of community health at Tufts University and first author of the study, also called attention to those birth cohorts.

"We see concerning trends for those born from around 1970 to 1985 - the late Gen Xers and elder Millennials," Abrams said. "These cohorts are trending worse than their predecessors in all-cause mortality, deaths from cardiovascular disease and cancer, especially colon cancer, and external causes."

These findings may seem to conflict with recent good news about life expectancy returning to levels found before COVID-19. But Mehta and his research team focused on data gathered before the pandemic.

"All of the behavioral and social factors-everything that is embedded within our bodies and our population-they're still here with us," Mehta said. "That's why it was really important to look at where we were before COVID, which is what we did in this paper. Even though life expectancy was stagnant, cancer mortality had been improving, until we got to some of these younger age groups where we suddenly saw upticks in some types of cancer mortality, especially in those born after 1970. But even in the 1950 and 1960s cohort, we started seeing these sorts of upticks for certain cancers, colon cancer being one of them."

The study didn't specifically look for causes for these changes.

"We looked at heart disease and specific cancers," Mehta said. "We looked at external causes like drug overdose and homicide. Many of these causes were trending poorly. We concluded that we have some very serious challenges in the U.S. as we move forward."

Other researchers who contributed to the study are Octavio Bramajo (University of Zurich), Alyson van Raalte (Max Planck Institute for Demographic Research), and Mikko Myrskylä (Max Planck Institute for Demographic Research).