For the better part of a century, life expectancy in industrialized countries like the United States steadily improved. But during the past three decades—and particularly since 2010—the trend has slowed or, in some places, reversed for non-Hispanic white populations in the U.S. It’s been especially stark for 25- to 44-year-olds and for women, as well as in rural communities.

Those are the key findings of research from University of Pennsylvania demographers Irma Elo and Samuel Preston and colleagues, which they published in the journal Population and Development Review.

“The trends vary by region,” says Elo, a professor of sociology and part of Penn’s Population Studies Center (PSC). “Large central metropolitan areas have done extremely well, particularly compared to the non-metropolitan areas that have done poorly. To varying degrees, that pattern is evident across the country.”

In the past 10 or so years, the mortality trajectory of non-Hispanic whites in the U.S. has worsened, diverging from progress seen for Hispanic and non-Hispanic black populations. This prompted Elo and colleagues to take a closer look at what was happening with this population and why. They also broadened their focus to include adults as young as 25 and as old as 64.

To draw their conclusions, they analyzed age, sex, race/ethnicity, and cause-of-death data compiled by the National Center for Vital Health Statistics, then estimated death rates by age, year, and geographic region. Finally, they distilled the data into four locality categories: large central metropolitan areas, large metro suburbs, small/medium metros, and non-metros.

“The biggest contrast we saw was between large metropolitan areas and their suburbs and non-metropolitan areas, which have moved in different directions,” says Preston, a Penn professor of sociology and member of the PSC. “Between 1990 and 2016, non-metropolitan areas had rising mortality, which is extremely unusual in the context of life expectancy that has gotten better nearly every year for nearly every group for more than a century.”

Women in general and younger adults also didn’t fare well, the former perhaps because of educational disparities, the latter largely due to drug overdoses. Though the opioid epidemic initially seemed gravest in Appalachia and other non-metropolitan areas, it has since proven much more widespread.

It’s one plausible cause for the bleak mortality trends for non-Hispanic whites as a whole. Elo and Preston also point to increases in mortality from mental and nervous-system disorders and respiratory disease, likely a lingering result of the smoking epidemic.

“Compared to other countries in 1990, the U.S. started out doing very poorly, and we are now in a much worse situation,” says Preston. “But there are two pieces of good news: The decline in HIV/AIDS mortality has been important in all central metros, but particularly in the mid-Atlantic, south Atlantic, and some of the Pacific region. And there have been declines in cardiovascular diseases pretty much everywhere.”

Plus, he adds, deaths from screenable cancers like prostate, breast, cervical, and colon cancer are down in all areas, too.

Other in-progress research from this team looks at non-Hispanic black populations and the U.S. population as a whole. But Elo says the work this paper highlights is an important step toward grasping and potentially reversing the negative trend. “There’s a lot to be done to try to understand what’s driving these patterns and, most importantly, what could be done to change them,” she says. “I don’t think anyone has the crystal ball yet for how to do it.”

Funding for this research came from the Robert Wood Johnson Foundation (grant 74439), the National Institute on Aging (grants R01AG060115, P30AG012836, and P30AG043073), and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (grants P2CHD047879 and R00HD083519).

Irma Elo is a professor and chair of the Department of Sociology in the School of Arts and Sciences and a research associate at the Population Studies Center at the University of Pennsylvania.

Samuel Preston is a professor in the Department of Sociology in the School of Arts and Sciences and a research associate at the Population Studies Center at the University of Pennsylvania.

Other researchers who contributed to the work include Arun Hendi of Princeton University, Jessica Ho of the University of Southern California, and Yana Vierboom of the Max Planck Institute for Demographic Research.