Trying to understand the reasons for the high rates of cancer among young people has raised many questions, given that all traditional risk factors, except for obesity, are still in steady decline.
Montserrat Garcia-Clauzas of the Institute of Cancer Research in London said, "The main conclusion is that although body mass index ( obesity ) is our best indicator, a large part of the increase in cancer rates remains unclear."
Globally, there has been a rise in cancer rates among adults under the age of 50. Since the 1990s, the incidence of colorectal cancer has increased by about 50% in many countries , including the United States, Australia, and Canada.
In search of the reasons, epidemiologists at the Institute of Cancer Research (ICR) studied cancer incidence trends in England and compared them with the dynamics of risk factors, publishing their findings in the journal BMJ Oncology.
According to statistics, up to 2019, there was an increase in the incidence of 11 types of cancer among people aged between 20 and 49 years, with colorectal cancer and breast tumors being the most prominent.
For nine of these eleven types, there is also a rise in infection rates among English people over the age of 50.
The researcher said that this suggests there are certain common reasons behind this increase.
The association was examined with major risk factors , including alcohol use , smoking , low physical activity, body mass index (obesity), fiber consumption, and consumption of processed or red meat , noting that the role of these factors is the most scientifically proven.
It turned out that all these indicators were decreasing or stable, except for body mass index (obesity). However, obesity alone cannot explain even a small part of the increase in incidence rates.
Professor Mark Gunter of Imperial College London, co-author of the study, said: "Many studies are now trying to pinpoint the exact causes of this phenomenon. Among the possible causes are increased consumption of ultra-processed foods , and so-called ' perennial chemicals ' such as antibiotics that disrupt the balance of the gut microbiome ."
The analysis showed that the increase in cancer rates among young people is likely due to a combination of factors, not just one. Improved diagnostic methods may also play a role.
Furthermore, study co-author Amy Berrington of the Institute of Cancer Research cautions that the findings must be considered in context. For example, only 3,000 young English people are diagnosed with colorectal cancer each year, meaning a 3% increase would translate to approximately 100 additional cases.
Berrington emphasizes that "these relative changes for a disease that is still rare mean that the absolute number of additional cases remains very small."
