The appearance of cancer has commonly been associated with aging, to the point that the appearance of this disease in young people shocks us. This can be attributed to the fact that, with greater age, there is a greater accumulation of cellular damage, more time of exposure to environmental factors, and a greater probability that a cell acquires alterations capable of transforming it into cancer. However, in recent decades, a trend has emerged that worries physicians, researchers, and health systems: more and more cancers are being diagnosed in young adults.
A recent study published in Nature Medicine, titled “Biological aging and generational shifts in early-onset cancer risk,” proposes a key idea to understand this phenomenon: perhaps it is not only important how many years a person has lived, but how “aged” their body is biologically. In other words, two people may have the same chronological age, for example 40 years old, but one of them may show biological signs more similar to those of an older person. This difference is known as the biological age gap, or age gap.
Cancer in Young People: A signal we should not ignore
Early-onset cancer generally refers to tumors diagnosed in adults younger than 50 or 55 years old. Although it remains less frequent than cancer at older ages, its sustained increase has generated concern. The study indicates that, between 1990 and 2019, cancers diagnosed before the age of 50 increased globally. In addition, this increase appears to be more pronounced in recent generations.
This means that people born in more recent decades may be facing risks different from those of previous generations. Not necessarily because their genetics have changed, but because the environment, habits, diet, sleep, sedentary behavior, exposure to pollutants, metabolic stress, and other modern factors may be affecting the biology of the body from earlier ages.
This is where the concept of biological age comes in. Chronological age is simple: the years that have passed since birth. Biological age, on the other hand, attempts to measure the real state of the body. It is a way of asking: are the tissues, immune system, metabolism, and organs functioning as expected for that age, or do they show signs of premature wear?
What is biological age and how is it measured?
Biological age is not calculated by looking at just one thing. It is not enough to measure a wrinkle, a glucose level, or an inflammatory marker. In this study, the researchers used different “biological clocks,” that is, tools that combine multiple clinical and molecular data to estimate how aged the body appears to be.
One of these methods was PhenoAge, which uses clinical biomarkers related to health, inflammation, metabolic function, and disease risk. Other methods were also evaluated, such as the Klemera-Doubal Method and a clock based on metabolomics, that is, on small molecules related to metabolism. In addition, the researchers explored organ-specific aging using proteomic data, analyzing proteins in blood that may reflect the state of tissues such as the immune system, adipose tissue, or lung.
The central idea was to observe whether people with a biological age more advanced than their chronological age had a higher risk of developing cancer at earlier ages.
What the study found
The main analysis included more than 154,000 young adults from the UK Biobank, a large biomedical database from the United Kingdom. The researchers observed that more recent generations showed a larger biological age gap. For example, people born between 1965 and 1974 had a 23% increase in the age gap compared with those born between 1950 and 1954.
This point is important because it suggests that accelerated biological aging may not only be an individual phenomenon, but also a generational one. Modern living conditions may be pushing the body toward a state of greater physiological wear from earlier stages of life.
In addition, the study found that greater biological age was associated with a higher risk of early-onset solid cancers. For each increase in the biological age gap, the risk of early solid cancer increased. The association was especially marked in some types of cancer such as lung, gastrointestinal, and uterine cancer.
Why could biological aging favor cancer?
Cancer does not appear overnight. It generally arises when a cell accumulates alterations and, in addition, finds an environment that allows it to survive, multiply, and escape the body’s controls. For this reason, cancer does not depend only on mutations; it also depends on the “terrain” where those cells live.
A biologically older body may have more chronic inflammation, lower repair capacity, immune alterations, metabolic changes, and tissues less capable of maintaining balance. All of this can create a more permissive environment for abnormal cells to progress toward a tumor.
In older adults, aging can have complex effects: sometimes it favors cancer, but in other contexts it also limits cellular proliferation capacity. In young adults, however, accelerated biological aging could represent a dangerous combination: tissues still capable of growth and regeneration, but exposed to signals of inflammation, metabolic stress, and immune dysregulation.
The role of the immune system, adipose tissue, and metabolism
One of the most interesting aspects of the study was the analysis of organ-specific aging. The researchers found that aging of the immune system was associated with a higher risk of early-onset lung cancer. This makes biological sense, since the lung is constantly exposed to the environment: polluted air, smoke, particles, infections, and other irritants. If the immune system ages or remodels prematurely, it could lose precision in controlling damaged cells or responding adequately to chronic insults.
It was also observed that aging of adipose tissue was associated with a higher risk of early-onset colorectal cancer. Adipose tissue is not only a fat reserve; it acts as a metabolic and inflammatory organ. It can produce signals that influence insulin, metabolism, systemic inflammation, and communication with the intestine. When adipose tissue becomes dysfunctional, it can alter the intestinal microenvironment and contribute to conditions that favor the appearance of cancer.
It is not just genetics
A relevant finding is that the association between advanced biological age and early cancer remained even after adjusting for genetic predisposition related to aging and cancer. This does not mean that genetics is not important. Genetics can always influence individual risk. But the study suggests that biological age captures something additional: the accumulated impact of the environment, lifestyle, exposures, and the physiological state of the body.
Figure 1. Modern lifestyle and environmental factors may accelerate systemic biological aging, promoting immune dysregulation, metabolic stress, and cellular damage. This increased biological age gap may be linked to a higher risk of early-onset cancers, including lung, colorectal, and uterine cancer.
Does this mean that biological age causes cancer?
Not necessarily. The study is observational, which means that it identifies associations, but does not prove direct causality. It cannot be concluded that having a higher biological age causes cancer by itself. There may also be unmeasured factors that influence both biological aging and cancer risk.
However, the results are important because they open a very relevant line of research. If future studies confirm these findings, biological clocks could help identify people at higher risk before the disease appears. They could also guide more personalized prevention strategies, focused not only on detecting cancer early, but also on improving the biological terrain that favors its appearance.
A new way to think about prevention
Cancer prevention usually focuses on well-known recommendations: not smoking, maintaining a healthy weight, exercising, reducing alcohol consumption, improving diet, and participating in screening programs when appropriate. All of this remains fundamental. But this study suggests that we should also pay attention to the body’s overall biological state.
Reducing chronic inflammation, improving metabolic health, protecting sleep, limiting sedentary behavior, caring for gut health, and reducing harmful environmental exposures could be important pieces to slow biological aging processes. Not as a promise of “rejuvenation,” but as a realistic strategy to keep tissues more functional and resilient.
Main reference:
Tian, R., Zong, X., Ren, D., Tica, S., Hong, D., Oduyale, O., Buenrostro, J. D., Govindan, R., & Cao, Y. (2026). Biological aging and generational shifts in early-onset cancer risk. Nature Medicine. https://doi.org/10.1038/s41591-026-04448-w
Other references:
Mak, J. K. L., McMurran, C. E., Kuja-Halkola, R., Hall, P., Czene, K., Jylhävä, J., & Hägg, S. (2023). Clinical biomarker-based biological aging and risk of cancer in the UK Biobank. British Journal of Cancer, 129(1), 94–103. https://doi.org/10.1038/s41416-023-02288-w
Moqri, M., Herzog, C., Poganik, J. R., Ying, K., Justice, J. N., Belsky, D. W., Higgins-Chen, A. T., Chen, B. H., Cohen, A. A., Fuellen, G., Hägg, S., Marioni, R. E., Widschwendter, M., Fortney, K., Fedichev, P. O., Zhavoronkov, A., Barzilai, N., Lasky-Su, J., Kiel, D. P., … Ferrucci, L. (2024). Validation of biomarkers of aging. Nature Medicine, 30(2), 360–372. https://doi.org/10.1038/s41591-023-02784-9
