A person may celebrate their thirtieth birthday and officially be 30 years old. But according to scientists, their body might actually look much older on the inside.
This idea is known as biological aging, and new research suggests it could play an important role in the growing number of cancers being diagnosed in younger adults.
Researchers from Washington University School of Medicine in St. Louis recently reported that younger generations appear to be aging faster biologically than previous generations. Their findings were published in Nature Medicine and may help explain why early-onset cancers are becoming more common around the world.
Early-onset cancer refers to cancer diagnosed at age 55 or younger. Over the past few decades, doctors have seen increases in several types of these cancers. Colorectal cancer in young adults has received a great deal of attention, but rises have also been reported in lung, uterine, and other cancers. Scientists have been searching for reasons behind these trends.
The new study focused on the difference between chronological age and biological age. Chronological age simply counts the number of years a person has been alive. Biological age is more complicated. It reflects how well different organs and body systems are functioning. Two people can have the same birthday yet have very different biological ages.
To investigate this issue, the researchers analyzed health information from two enormous studies. One included more than 154,000 people from the United Kingdom, and the other included more than 10,000 people from the United States. The scientists examined blood markers related to metabolism, organ function, and aging processes throughout the body.
They also looked at proteins linked to specific organs and tissues. This allowed the researchers to estimate not only overall biological aging but also the aging of particular body systems, such as the immune system and fat tissue.
The findings showed a clear pattern. People born more recently tended to have bodies that appeared biologically older than those of earlier generations when they reached the same age. The shift was noticeable in both countries that were studied.
The researchers then examined whether accelerated aging was related to cancer risk. They found that people with greater biological aging faced an increased risk of developing cancer at younger ages. Those with the highest levels of biological aging had a 15% greater risk of early-onset solid cancers than people with the lowest levels.
The study also found links between specific body systems and particular cancers. An immune system that appeared older than expected was associated with a higher risk of early-onset lung cancer. Fat tissue that appeared biologically older was linked to a greater risk of early-onset colorectal cancer.
These findings raise an important question. Why might younger generations be aging faster?
Scientists do not yet know the full answer. They believe many influences probably work together. Obesity has increased in many countries, and metabolic conditions such as insulin resistance and fatty liver disease have become more common. Modern diets often contain more highly processed foods and sugary drinks.
Many people are physically inactive and spend much of their day sitting. Sleep problems and stress are also widespread. Environmental exposures that have changed over recent decades may also be involved.
The researchers think accelerated aging may act like a summary of many different risk factors combined. Instead of looking at one factor at a time, biological age may reveal the overall burden that lifestyle and environmental changes place on the body.
The study points toward a possible future in which doctors can identify people at high risk before they become ill. Measuring biological aging could help guide earlier screening and more personalized prevention strategies. People found to be aging faster may benefit from closer monitoring or interventions designed to improve their long-term health.
This research does not prove that accelerated aging directly causes cancer. It only shows that the two are strongly linked. More studies are needed to understand exactly how modern environments and lifestyles affect biological aging and cancer risk.
Even so, the findings provide an important piece of the puzzle. They suggest that the rise in cancer among younger adults may not simply be a matter of bad luck or genetics.
Instead, changes happening across the body over time may be quietly increasing vulnerability to disease. By understanding these changes better, scientists hope to shift medicine away from reacting to cancer after it appears and toward preventing it long before it begins.
If you care about cancer, please read studies that a low-carb diet could increase overall cancer risk, and vitamin D supplements could strongly reduce cancer death.
For more information about health, please see recent studies about how drinking milk affects the risks of heart disease and cancer and results showing higher intake of dairy foods linked to higher prostate cancer risk.
Source: Washington University School of Medicine in St. Louis.
