Cancer has long been considered a disease associated with getting older. But an increasing number of people are being diagnosed at younger ages, raising questions about what may be driving the trend.

Now, researchers have identified a potential piece of the puzzle: biological ageing.

A study published in Nature Medicine found that people from more recent generations tended to show signs of faster biological ageing than earlier generations at the same chronological age. The researchers also found that greater biological ageing was associated with a higher risk of developing cancer before age 55.

What Is Biological Ageing?

Chronological age is simply the number of years a person has lived. Biological age, however, reflects how old the body appears based on measurable changes involving cells, organs and metabolism.

Researchers can estimate biological ageing using markers found in blood and other biological data. In this study, scientists used several established measures, including PhenoAge, the Klemera-Doubal method and metabolomic-based ageing measures. They also examined organ-specific ageing using blood protein data.

The researchers analysed data from 154,169 people in the UK Biobank and validated some of their findings using data from 10,262 participants in the US All of Us Research Programme.

Read more

Younger Generations Appeared to Be Ageing Faster

The differences between generations were particularly striking in the US data. Participants born between 1990 and 1999 had systemic biological ageing that was 92% of a standard deviation higher than people born between 1965 and 1969.

In the UK, people born between 1965 and 1974 had biological ageing measures that were 23% of a standard deviation higher than those born between 1950 and 1954, after chronological age was taken into account.

The findings also appeared to have implications for cancer risk.

Greater systemic biological ageing was associated with an 8% higher risk of early-onset solid cancers per standard deviation increase. When researchers compared people with the highest third for systemic ageing with those in the lowest, the former group had a 15% higher risk of early-onset solid cancer.

The strongest associations involved lung, gastrointestinal and uterine cancers.

Which Body Systems Could Matter?

The researchers also found links between ageing in specific biological systems and certain cancers.

More advanced immune-system ageing was associated with a higher risk of early-onset lung cancer, while faster ageing of adipose, or fat, tissue was associated with early-onset colorectal cancer. These associations remained after researchers accounted for inherited genetic risks linked to cancer and biological ageing.

However, the findings do not prove that accelerated biological ageing directly causes cancer. Researchers say the rise in early-onset cancer is likely influenced by multiple factors, including obesity, metabolic health, alcohol consumption, physical inactivity and diet.

The study instead suggests that biological ageing could provide a broader way of understanding how several exposures may accumulate and influence cancer risk over time.

Further research will be needed to establish what is accelerating biological ageing in younger generations and whether measuring biological age could eventually help identify people who might benefit from earlier prevention or cancer screening.

Read more