Younger Generations Are Aging Faster, and It May Explain the Rise in Early-Onset Cancer

Cancer has long been thought of as a disease that catches up with us as we age, the longer we live, the more time our cells have to accumulate damage. So why are more and more people under 55 being diagnosed with it? A new study led by researchers at Washington University School of Medicine in St. Louis points to a surprising possible answer: younger generations may simply be aging faster on the inside than their birth certificates suggest, and that accelerated biological aging appears to be driving up their cancer risk.

Biological age vs. chronological age

The research team, led by molecular epidemiologist Yin Cao, ScD, distinguished between two kinds of “age”: chronological age (how many birthdays you’ve had) and biological age (how old your body’s tissues and systems actually appear based on molecular markers). The gap between these two numbers, the “age gap”, turns out to matter a lot. The wider that gap, the higher a person’s risk of developing cancer before age 55.

To measure this, the team analyzed data from more than 154,000 adults in the UK Biobank and over 10,000 participants in the NIH’s All of Us Research Program in the US. They used established biological-aging tools, including blood biochemistry-based measures like PhenoAge, alongside metabolomic and proteomic data that can flag aging happening in specific organs rather than just the body as a whole.

Each generation, an older-looking biology

The pattern held in both countries: people born more recently showed larger age gaps than those born decades earlier, even after accounting for how many years they’d actually lived. In the UK cohort, people born in the early-to-mid 1970s showed meaningfully more advanced systemic aging than those born in the early 1950s. In the US cohort, the shift between generations born in the 1990s versus the 1960s was even larger.

That increased systemic aging tracked with an 8% higher risk of early-onset solid cancers overall, and people with the most advanced aging profiles had a 15% higher risk than those with the least. Crucially, the effect held up even after the researchers controlled for inherited genetic cancer risk, this isn’t just about the genes you were born with.

Different organs, different cancers

The most intriguing part of the study zooms in on individual organ systems. When the immune system showed signs of aging faster than the rest of the body, that was linked specifically to a higher risk of early-onset lung cancer. When fat (adipose) tissue aged faster, that was linked to early-onset colorectal cancer. It’s a hint that different organs may be quietly aging on their own timelines, and that the specific organ under strain could point toward the specific cancer type at risk.

Cao described the team’s goal as decoding how modern environments become biologically embedded to drive cancer risk, with the aim of shifting cancer prevention from broad recommendations toward interventions tailored to a person’s own biology.

The obvious next question, what’s actually causing this accelerated aging in younger generations, remains unanswered. Diet, sedentary lifestyles, obesity, alcohol use, and even mode of birth (cesarean vs. vaginal delivery) have each been flagged in Cao’s prior work as modest individual contributors, but no single factor explains the shift. The current study, part of the Cancer Grand Challenges-funded Team PROSPECT, was designed to capture how many such factors act together rather than in isolation.

If biological age gaps really do predict cancer risk, they could eventually become a screening tool: a way to flag which younger, currently healthy people would benefit most from earlier cancer screening or prevention efforts, long before a tumor ever shows up.

Original paper: Tian R, Zong Y, Ren D, et al. “Biological aging and generational shifts in early-onset cancer risk.” Nature Medicine, June 22, 2026. DOI: 10.1038/s41591-026-04448-w

Source press release: WashU Medicine — “Faster aging in younger generations linked to rise in early-onset cancer” 

Source: Younger Generations Are Aging Faster, and It May Explain the Rise in Early-Onset Cancer