The research, conducted by the Institute of Cancer Research (ICR), shows that cancers associated with obesity including thyroid, breast, kidney, endometrial and leukaemia—are increasing at similar rates among both younger and older people.
Concerns about early onset cancer have gained attention in recent years following the diagnoses of public figures such as the Princess of Wales, Dame Deborah James, and Sarah Harding, all before the age of 50. However, the new study challenges the idea that the rise in obesity-related cancers is mainly a young person’s problem.
Researchers compared cancer trends across 42 countries over a 15-year period and found that, in three quarters of them, these cancers increased consistently across all adult age groups. The only exception was bowel cancer, which showed a faster rise in people under 50.
Between 2003 and 2017, thyroid cancer saw the sharpest increase among younger adults, rising by an average of 3.6 per cent per year. This was followed by kidney cancer at 2.2 per cent, endometrial cancer at 1.7 per cent, bowel cancer at 1.5 per cent, and both breast cancer and leukaemia at just under 1 per cent. Older adults showed similar increases.
Bowel cancer was the outlier, with incidence rates growing by 1.45 per cent each year in younger adults compared with 0.4 per cent among older people. The study authors suggested that screening programmes for bowel cancer in older adults could be preventing some cases, slowing the rise in that age group.
The findings, published in the Annals of Internal Medicine, suggest that rising obesity rates could be a shared factor driving cancer across all generations.
Professor Amy Berrington, team leader in clinical cancer epidemiology at the ICR, said:
“Our findings suggest that whatever is triggering the rise in these cancers is more likely to be common across all age groups rather than specific to younger adults. Several studies have suggested that obesity could be a major contributor.”
She added that researchers are investigating how much of the increase can be attributed to obesity, and whether other environmental or lifestyle factors might also be playing a role.
Professor Kristian Helin, chief executive of the ICR in London, said:
“There has been considerable concern about a potential epidemic of cancer among younger adults. These results show that the rise is not limited to one age group and underline the importance of developing strategies that include all adults.”
Professor Berrington also highlighted that bowel cancer screening not only detects the disease earlier but can also prevent it by removing pre-cancerous growths.
“This could explain why we’re seeing faster rises in younger adults,” she said. “We’re becoming better at preventing cases among older adults.”
