A new study has identified obesity as a key factor behind the rising rates of cancer among younger adults in England. Researchers from the Institute of Cancer Research and Imperial College London analysed data from 2001 to 2019 and found that 11 types of cancer, including bowel and ovarian cancer, are increasing in people aged 20 to 49.
Obesity was the only known behavioural risk factor that increased among younger adults during this period, while smoking, alcohol consumption, red meat intake and physical inactivity remained stable or declined. The researchers linked excess weight to 10 of the 11 cancers identified, including thyroid, kidney and pancreatic cancer, with oral cancer being the only exception. Maintaining a healthy weight could prevent around 20% of bowel cancers, 35% of endometrial cancers and 27% of kidney cancers, they said.
Professor Montserrat García-Closas, co-director of the Cancer Epidemiology and Prevention Research Unit at the Institute of Cancer Research, said: "Excess weight is an important contributor, although it cannot fully account for the scale of the rise in bowel and other cancers. This tells us that multiple factors – including early-life exposures – may be acting together." She called for tackling obesity across all ages, particularly in children and young people, through stronger public health policies.
Michelle Mitchell, chief executive of Cancer Research UK, emphasised that the picture is complex: "Overweight and obesity doesn't explain the rise in full. Improvements in detection are likely to also be playing a part." She urged the UK government to prioritise cancer prevention by restricting junk food advertising, introducing mandatory healthy food sales targets and making nutritious food more accessible.
The study comes amid record high cancer diagnoses in the UK, with one person diagnosed every 80 seconds and over 403,000 cases each year. While the increase in under 50s mirrors trends in older age groups, bowel and ovarian cancer rates rose only among younger people, at 3% and 0.7% per year respectively. The researchers noted that obesity alone does not account for the overall rise, suggesting unknown causes may also be at play.
