Are Young People Aging Faster? New Study Links “Biological Age” to Rising Cancer Risk

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Two 40-Year-Olds, Two Different Bodies

Your calendar age counts the years since your birth. Your biological age asks a different question: how worn is your body, judged by blood markers, metabolism and inflammation?

Two people can both turn 40 on the same day. One may have the body of a typical 35-year-old, the other that of a typical 47-year-old.

Researchers at Washington University School of Medicine in St. Louis wanted to know whether that gap is growing from one generation to the next. They also asked whether it helps explain why cancer is now diagnosed more often in younger adults. Their findings were published on June 22, 2026, in Nature Medicine.

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What the Researchers Found

The team analyzed data from more than 154,000 adults in the UK Biobank, a large British health database. They then checked their results against more than 10,000 people in the U.S. National Institutes of Health's "All of Us" research program.

To estimate biological age, they used blood tests and measures of metabolism. These included PhenoAge, a method that looks at nine blood markers, among them markers of liver and kidney function. They also used blood proteins to estimate the age of individual organs.

The main results:

• Younger generations look "older." In the UK group, people born in 1965–1974 had a biological age gap 23% of one standard deviation higher than people born in 1950–1954. A standard deviation is a statistical measure of how spread out the data is. In the U.S. group, people born in 1990–1999 showed a gap 92% of one standard deviation higher than those born in 1965–1969.
• A bigger gap meant more cancer. Each step up in the aging measure came with about 8% higher risk of early-onset solid cancers. People in the highest third had a 15% higher risk than those in the lowest third. Lung, digestive-tract and uterine cancers stood out.
• Organs age at different speeds. An older-looking immune system was tied to early-onset lung cancer. Older-looking fat tissue was tied to early-onset colorectal cancer.

The researchers say the link held even after they accounted for inherited genetic risk.

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Why This Matters Now

"Early-onset" cancer means cancer diagnosed at age 55 or younger. Doctors have noticed more of these cases for years. A study in The Lancet Oncology found that colorectal cancer in people under 50 rose in 27 of the 50 countries examined between 2013 and 2017.

Another analysis reports that in Australia, Canada, the UK and the U.S., people born in the 1990s have about four times the risk of early-onset colorectal cancer of those born in the 1960s.

Scientists still lack a definitive explanation. The World Cancer Research Fund describes the rise in young adults as unexplained. The director of Cancer Grand Challenges, a major research initiative, said no one yet knows what is driving it.

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The Likely Suspects

The new study did not identify a cause. Other research points to several candidates that may act together:

• Ultra-processed food. A study from Mass General Brigham followed nearly 30,000 younger women. It found that higher intake of ultra-processed foods went with more colorectal adenomas, which are precancerous growths.
• Excess weight, diabetes and inactivity. These are well-known risk factors for early colorectal cancer.
• Gut health and antibiotics. Scientists are studying changes in gut bacteria, though the evidence is still developing.

Not everything fits neatly. A review in Frontiers in Public Health notes that obesity and a sedentary lifestyle do not appear to explain early-onset colorectal cancer in all patients. The picture is still incomplete.

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What It Means for You

A biological-age test is not yet a routine medical tool. The study's authors say such measures might one day help doctors spot higher-risk young people while they are still healthy and offer them earlier screening.

Meanwhile, the researchers note that unlike our genes, many of the influences on biological aging can be changed. Health authorities consistently recommend a few sensible steps:

• Eat more whole foods and fewer ultra-processed products. Home cooking helps you control what goes in.
• Move regularly and avoid long stretches of sitting.
• Sleep enough, and don't smoke or drink heavily.
• Don't ignore persistent warning signs such as changes in bowel habits, ongoing abdominal pain or unexplained weight loss. Talk to a doctor.

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Outlook

The study cannot say whether faster aging causes cancer or whether both share common causes. The next task for researchers is to find which exposures speed up the biological clock, and whether slowing it lowers cancer risk.

For now, the message is cautious but practical. Your birth certificate sets your age, but daily habits seem to shape how old your body acts.

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Sources

1. Tian R, et al. "Biological aging and generational shifts in early-onset cancer risk." Nature Medicine, June 22, 2026. https://doi.org/10.1038/s41591-026-04448-w
2. WashU Medicine / The Source, "Faster aging in younger generations linked to rise in early-onset cancer": https://source.washu.edu/2026/06/faster-aging-in-younger-generations-linked-to-rise-in-early-onset-cancer/
3. Technology Networks, "Faster Biological Aging Could Explain Rise in Cancer Rates in Younger Adults": https://www.technologynetworks.com/cancer-research/news/faster-biological-aging-could-explain-rise-in-cancer-rates-in-younger-adults-413917
4. World Cancer Research Fund, "Investigating colorectal cancer in young adults": https://www.wcrf.org/research-policy/our-research/grants-database/investigating-colorectal-cancer-in-young-adults/
5. KTVU, "New study links ultra-processed foods to rising colon cancer risk among young adults": https://www.ktvu.com/news/new-study-links-ultra-processed-foods-rising-colon-cancer-risk-among-young-adults
6. Straight Arrow News, "Colorectal cancer surging in young people worldwide: Study" (The Lancet Oncology): https://san.com/cc/colorectal-cancer-surging-in-young-people-worldwide-study/
7. Frontiers in Public Health, review on early-onset colorectal cancer, gut microbiome and diet: https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2024.1370108/pdf

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