Cancer has always been considered a disease whose risk increases with age. This is because the longer a person lives, the more time their cells have to accumulate damage that can eventually contribute to the development of a tumor. At the same time, researchers worldwide are observing that certain types of cancer are occurring with increasing frequency even among younger adults. This trend raises an important question: Could it be that younger generations are aging biologically faster and, as a result, are developing changes at an earlier age that increase their risk of cancer? A new study led by Washington University School of Medicine in St. Louis provides evidence to support this. The scientists found indications that people from younger generations, at the same chronological age, sometimes exhibit more pronounced signs of biological aging than people from earlier generations.
Why these changes develop has not yet been conclusively determined. Researchers from various countries are therefore working to better understand the possible causes. This includes the international research project Team PROSPECT, which is supported by the “Cancer Grand Challenges” program. Another finding from the study is particularly relevant: more pronounced biological aging was associated with an increased risk of certain cancers in younger adults—cancers that can occur as early as age 55 or younger.
When Biological Age Differs from Actual Age
Chronological age is easy to determine: it corresponds to the number of years that have passed since birth. Biological age, on the other hand, describes the body’s actual condition. It takes into account, among other things, changes in cells, organs, metabolism, and other physiological systems. The researchers therefore investigated the extent to which biological age differed from actual chronological age. Their findings showed that people born in more recent years were more likely to have a greater discrepancy between the two values.
In other words: At the same chronological age, the bodies of younger generations sometimes appeared biologically older than those of people born earlier. This difference could potentially explain part of the increasing incidence of certain cancers among younger adults.
The study also showed that biological aging processes do not proceed at the same rate in all organs and body systems. For example, more advanced aging of the immune system was associated with a higher risk of early-onset lung cancer. In contrast, adipose tissue that appeared biologically older was linked to an increased risk of colorectal cancer.
Could Biological Aging Help with Cancer Prevention?
If the results of the study, which were published in the journal*Nature Medicine*, are confirmed by further research, measurements of biological age might one day help identify people with an unusually high risk of cancer at an earlier stage. In the long term, this would open up the possibility of using preventive measures or specific early-detection screenings in a more targeted manner.
Yin Cao, ScD, a molecular epidemiologist and associate professor of surgery and medicine at WashU Medicine, sees this as an important step toward more personalized cancer prevention. Her goal is to better understand how modern lifestyles trigger biological changes in the body and thereby potentially influence cancer risk. These findings could help tailor prevention efforts more closely to an individual’s biology in the future.
Individual Risk Factors Alone are Not Sufficient to Explain the Phenomenon
Cao and her team have already examined numerous factors that can influence cancer risk over the course of a person’s life. These include, among others, obesity, metabolic disorders, alcohol consumption, physical inactivity, and poor diet quality. Factors related to cesarean delivery were also investigated.
Each of these aspects can contribute to an individual’s cancer risk. However, none of these factors alone appears to explain why certain types of cancer are more common among younger people worldwide. Therefore, the scientists sought a way to consider the combined effects of various stressors. Biological aging could serve as a kind of overarching metric in this context. It could reflect the extent to which these various influences affect the body over the course of a lifetime.
For the current study, the researchers analyzed extensive health data from two large population cohorts. Information from more than 154,000 young adults was evaluated from the UK Biobank. The database contains extensive data on health, biological characteristics, and lifestyle.
In addition, the scientists examined more than 10,000 participants in the U.S. National Institutes of Health’s “All of Us” research program. This project aims to build a comprehensive health database containing information from more than one million people in the United States.
By combining these data, the researchers were able to investigate whether differences in biological aging can be identified across different generations and whether these differences are associated with an increased risk of cancer.
How Fast does the Body Actually Age?
For their analyses, the scientists examined both the aging of the entire body and the aging of individual organ systems. To determine systemic biological age, they used established methods such as PhenoAge and the Klemera-Doubal method, among others. In addition, they used a metabolomic age index that accounts for typical age-related changes in metabolism.
PhenoAge, for example, is based on nine biochemical blood markers. These include albumin, which is produced in the liver, and creatinine, a metabolic byproduct excreted by the kidneys. To study individual organs, the researchers also used so-called proteomic data, which involves analyzing numerous proteins in the blood. The different protein patterns can provide clues as to how old certain organs or biological systems appear from a biological perspective. The scientists then compared the participants’ biological and chronological ages and examined the differences between different birth cohorts.
Particularly Pronounced Differences Among the Younger Cohorts
The results showed a similar trend in both the British and U.S. data. In the UK Biobank, people born between 1965 and 1974 exhibited systemic aging that was 23 percent of a standard deviation higher than that of individuals born between 1950 and 1954. This analysis already took chronological age into account.
The difference was even more pronounced in the U.S. group. Participants born between 1990 and 1999 exhibited systemic aging that was 92 percent of a standard deviation higher than that of people born between 1965 and 1969.
Put simply, this means that when people from different age cohorts are compared at the same chronological age, younger generations more frequently exhibit biological characteristics that indicate more advanced aging.
Accelerated Aging is Associated with a Higher Cancer Risk
The scientists then investigated whether differences in biological age were also linked to the development of cancer. They found that greater systemic biological aging was associated with an 8 percent higher risk of early-onset solid tumors. The associations were particularly pronounced for lung cancer, cancers of the gastrointestinal tract, and uterine cancer.
The participants were also divided into three groups based on the extent of their biological aging. Among those with the most pronounced systemic aging, the risk of early-onset solid cancers was 15 percent higher than among those with the fewest signs of accelerated aging. This association remained even after the researchers accounted for genetic factors. These included both hereditary cancer risks and genetic traits associated with accelerated aging.
It is already known from previous studies that certain types of cancer are increasingly occurring in younger adults. A review article published in 2022 in*Nature Reviews Clinical Oncology*evaluated global trends in so-called early-onset cancers. The term “early-onset cancer” is often used to describe cancers diagnosed before the age of 50.
The researchers found that the incidence of various types of cancer among younger adults has increased in many countries since the 1990s. These include breast, colorectal, uterine, esophageal, kidney, liver, pancreatic, stomach, and thyroid cancers. While more intensive screening may explain part of this trend, the authors
The Immune System and Adipose Tissue Exhibit Distinct Patterns
The examination of individual biological systems provided further interesting insights. More pronounced biological aging of the immune system was associated with an increased risk of early-onset lung cancer. In contrast, adipose tissue was found to be associated with a higher risk of colorectal cancer.
These findings make it clear that biological aging cannot be viewed as a uniform process. Different organs and tissues apparently age at different rates and may also have different effects on disease risk.
This could be an important approach for cancer research. In the future, the focus may not be limited to determining the biological age of the entire body. The biological aging of individual organs could also provide clues about specific disease risks.
Why is Cancer Risk Increasing Among Younger People?
Despite these new findings, one key question remains unanswered: Why do younger generations appear to age faster at the biological level? Researchers believe that several factors are at play. Environmental conditions, lifestyle, and societal changes could influence the body over long periods of time and alter biological processes.
Cao and her colleagues therefore want to investigate more closely how such influences accumulate over the course of a lifetime. They may leave lasting biological traces that accelerate aging processes and thereby increase susceptibility to certain diseases. David Scott, director of “Cancer Grand Challenges,” emphasizes that there is still no definitive explanation for the global rise in early-onset cancers.
However, current research could help bring the various findings together. In doing so, the focus is increasingly shifting not only to individual cancer cells but also to changes that affect the entire body.
The Goal is More Personalized Cancer Prevention
The study is part of Team PROSPECT, an international research consortium that Cao co-leads. The project is supported by “Cancer Grand Challenges.” The initiative was founded jointly by Cancer Research UK and the National Cancer Institute (NCI). It brings together scientists from various disciplines and countries to investigate particularly challenging questions in cancer research. One focus is on why certain types of cancer are occurring more frequently in younger adults.
Cao and her colleagues are particularly interested in understanding how the environment, lifestyle, and societal changes influence human biological development. The key question is when such changes begin and how they accumulate over the course of a person’s life. In the long term, this research could help identify people at increased risk of cancer while they are still healthy.
If reliable biological markers for an increased risk can be identified, prevention and early detection measures could potentially be applied in a more targeted manner. In this case, the focus would no longer be exclusively on chronological age, but also on the body’s biological state.
However, research is still a long way from such an application in general cancer screening. The current findings show a link between accelerated biological aging and certain cancers that occur at an early age. However, they do not prove that accelerated aging itself is the cause of the increase in these diseases.
Further studies are therefore needed to clarify which factors influence biological aging in younger generations and which biological processes are actually behind the increased cancer risk. The researchers’ long-term goal is clear: to identify people at increased risk as early as possible—ideally before cancer develops. In the long term, this could shift cancer medicine more strongly from general to individually tailored prevention.