Scientists say that younger generations are ageing biologically more quickly than previous generations, which could explain why some cancers have risen faster in young adults over the past decade, reports Healthline.
Researchers from the Washington University School of Medicine recently published a study in Nature Medicine suggesting that rapid cellular ageing may explain why certain cancers have risen sharply in younger people over the past 10 years or so.
They said that cancer can develop when genetic damage has accumulated in cells. When DNA is damaged, it can transmit flawed instructions, leading to malfunctions in cell division. That disruption can lead to cancer, and this type of damage is commonly seen as people age.
Ketan Thanki, MD, a colorectal surgeon specialising in benign and malignant disease of the colon, rectum and anus at the MemorialCare Todd Cancer Institute at Long Beach Medical Centre in California, said the new research provides valuable information.
“The study shows that using established markers of biological age, we have evidence that younger generations are ageing faster than previous generations,” he told Healthline.
“The study doesn’t pinpoint exactly why but points toward factors that research has been suggesting for years.”
Why are young adults ageing faster?
The researchers cited a 2021 study that identified several factors contributing to faster biological ageing. These included obesity and metabolic dysfunction; unhealthy diet; prolonged sedentary time; circadian disruption, and exposure to environmental chemicals.
However, the researchers said further studies are needed to determine why biological ageing has accelerated in younger generations.
“A better understanding of how generational differences in accelerated ageing relate to early onset cancers is needed urgently,” they wrote.
“This question is central because early onset cancers show strong birth-cohort effects, with more recent generations experiencing higher risk as they age.”
Younger generations have a higher ‘age gap’
To reach their findings, the researchers examined data on three generations of people listed in two data banks.
They studied blood markers from more than 150 000 adults in the UK Biobank, comparing people born in the early 1950s with those born in the late 1960s and early 1970s.
They also examined health data from more than 10 000 adults in the United States’ All of Us research programme – which includes people born from 1965 onward – comparing people born in the 1960s with those born during the 1990s.
Their primary metric was PhenoAge, a measure of biological ageing based on chronological age and nine blood biomarkers.
The team used that metric to calculate an “age gap” score to estimate whether a person appears biologically older or younger than expected for their actual age.
They found that younger generations appeared biologically older than the previous generations at the same chronological age.
People born in the United Kingdom between 1965 and 1974 had a 23% higher standardised PhenoAge-defined age gap than those born between 1950 and 1954.
Similarly, in the United States, people born during the 1990s had a 92% higher standardised age gap than those born between 1965 and 1969.
Higher ‘age-gap’ linked to early onset cancer risk
Using a subset of the data, the researchers examined whether the age-gap scores were associated with cancer risk.
They discovered that people with higher age-gap scores were more likely to develop cancer before age 55. This was particularly true with cancers of the lung, digestive system and uterus.
The researchers added that every increase in age-gap score increased the risk of early onset solid cancers by 8%. The strongest association was for lung cancer, in which the risk rose by 57%.
They reported that the associations persisted even after controlling for factors such as smoking, obesity, telomere length, and genetic predisposition.
Thanki said the trend was concerning.
“Age-related morbidities – diseases that we have previously associated with the elderly – will become more and more common in younger people,” he said. “Beyond the burden on individual quality of life, this will lead to greater healthcare costs as a society and potentially even a shortening of life expectancy.”
Thanki added that changes in how healthcare is approached need to be made.
“We are already facing clinical and diagnostic challenges in younger adults, meaning unless we change how and how well we screen, we will miss more cases and see more patients presenting with advanced disease.”
Alarming rise
There have been various reports in recent years noting the increase in cancer rates in younger adults. A 2023 study reported that early onset cancer rates increased by 79% globally from 1990 to 2019.
A 2025 study noted that in Australia, Canada, the United Kingdom, and the United States, people born in the 1990s face at least a fourfold higher risk of early onset colorectal cancer compared with those born in the 1960s.
In January 2026, the American Cancer Society (ACS) reported that colorectal cancer is now the leading cause of death due to cancer for people under 50 in the United States.
This increase comes despite the fact that overall cancer mortality has declined by 44% over the past three decades for this age group. In addition, cancer rates for people over 50 are also decreasing.
Experts say there are a number of factors that could be causing the rise in cancer risk in younger adults. These include:
higher rates of obesity;
greater consumption of ultra-processed foods and foods high in refined sugar;
lack of physical activity;
irregular sleep patterns;
exposure to carcinogenic chemicals.
There are lifestyle habits that younger adults can adopt to help lower their cancer risk.
These include:
a balanced, healthy diet with minimally processed foods;
regular aerobic and strength-oriented exercise;
limiting alcohol consumption; and avoiding tobacco use.
Screenings is one of the most effective tools for combatting cancer because most cancers are treatable if they are detected early, experts say.
“We really need to start rethinking our lifestyles,” said Thanki. “Our consumption of processed foods, alcohol, and environmental toxins, our levels of physical activity or inactivity, and what we consider healthy levels of body fat, will all need to be modified.
“The best interventions are often the simplest, though not necessarily the easiest,” he added.
Study details
Biological ageing and generational shifts in early-onset cancer risk
Ruiyi Tian, Xiaoyu Zong, Duo Ren, Stefani Tica et al.
Published in Nature Medicine on 22 June 2026
Abstract
Incidence of early-onset cancer is rising globally in recent generations, which underscores the need to elucidate the influence of emerging generational risk factors. Systemic and organ-specific ageing reflects the cumulative impact of exposures and may provide an integrative and complementary approach to understand early-onset cancer risk. Here among 154,169 young adults from the United Kingdom Biobank, systemic ageing measured by PhenoAge increased across birth cohorts, with 23% s.d. increase for those born 1965–1974 versus 1950–1954, and was associated with early-onset solid cancer risk (hazard ratio (HR)per s.d. 1.08; 95% confidence interval (CI), 1.03–1.13), driven by lung, gastrointestinal and uterine cancers, independent of genetic risks of ageing and cancer. Patterns were consistent using alternative systemic ageing measures, including the Klemera–Doubal method-defined age gap and metabolomic-based age gap. These findings were validated partially among 10,262 participants in the United States All of Us Research Program. Proteomics-based organ-specific ageing analyses linked immune ageing with early-onset lung cancer (HRper s.d. 1.89; CI, 1.20–2.97) and adipose tissue ageing to early-onset colorectal cancer (HR 1.60; CI, 1.11–2.32). Greater age gap, reflecting more advanced biological ageing relative to chronological age, may serve as a driver associated with risk of early-onset solid cancers, highlighting the importance of uncovering underlying mechanisms to guide effective prevention strategies.
Nature article – Biological ageing and generational shifts in early-onset cancer risk (Open access)
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Ageing population contributes to high cancer deaths in SA
Vitamin D may slow cells’ ageing – Harvard study
Cancer mortality may drop by 12% with daily vitamin D – Germany study
Why cancer in young people is on the rise – British analysis