Why do cancers affect more and more people before the age of 50? A new study published in Nature Medicine advances a new avenue: the most recent generations would present accelerated biological aging. A hypothesis which could help to explain the increase in early cancers, without establishing a cause and effect link.
Over the past thirty years, doctors have observed a worrying increase in cancers among adults under the age of 50. Although several factors are mentioned, the precise mechanisms remain poorly understood. A new study now sheds additional light on this phenomenon.
Faster biological aging in recent generations
According to a study published in the journal Nature Medicinepeople born between 1965 and 1974 would have a higher biological age than those born between 1950 and 1954. In other words, they would age more quickly at the molecular and cellular level at the same age.
The observation is even more marked among people born between 1990 and 1999, who would display even greater biological aging compared to previous generations.
To reach these conclusions, the researchers analyzed data from nearly 164,000 adults from the UK Biobank and All of Us cohorts. They assessed aging of the body as a whole as well as that of different organs using clinical biomarkers and a metabolic age score.
The results show that people born between 1965 and 1974 showed accelerated aging 23% higher than that observed in individuals born in the 1950s. In participants born between 1990 and 1999, this systemic aging was 92% higher than in those born between 1965 and 1969.
As Yin Cao, Ph.D., molecular epidemiologist, associate professor of surgery and medicine at WashU Medicine and co-author of the study, explains, biological aging reflects “wear and tear that occurs inside the body.” It can notably result in chronic inflammation, a weakening of the immune system and the accumulation of damage in cells over time.
A promising avenue for understanding the increase in early cancers
Since the 1990s, cancers among people under 50 have been on the rise. According to a report from the British Medical Journal, the number of new cases increased by 79% worldwide between 1990 and 2019.
The exact causes remain difficult to identify. Researchers particularly mention endocrine disruptors, microplastics, global warming, processed foods, alcohol and even a sedentary lifestyle, without it being possible to precisely determine their role.
The authors of the study published in Nature Medicine
however, insist on an essential point: their work does not demonstrate a cause and effect link between accelerated biological aging and the development of cancer. They highlight a correlation, which will need to be confirmed by further research.
For David Scott, director of Cancer Grand Challenges, this approach is nevertheless of major interest. It shows that cancer could be influenced not only by changes in the cancer cells themselves, but also by changes that affect the entire organism.
Researchers now hope to better understand how modern environments influence biological aging in order to identify people at risk earlier and ultimately develop more personalized prevention strategies.