Cancer is increasing in young people and we still don't know why

Cancer rates among young adults under 50 are rising globally, with colorectal (bowel) and breast cancers showing significant increases. A recent study analyzing data from England found that 11 types of cancer, including liver, kidney, and pancreatic cancers, have been increasing annually by 1 to 6 percent in this age group. While obesity, measured by body mass index (BMI), has worsened over time and may partly explain the trend, it accounts for only a fraction of the rise, leaving most of the causes unexplained. Researchers led by Montserrat Garcia-Closas at the Institute of Cancer Research examined known behavioral risk factors such as smoking, alcohol consumption, physical inactivity, fiber intake, and processed or red meat consumption. These factors have generally remained stable or improved, except for obesity, which has steadily increased. Despite obesity being a recognized cancer risk, it explains only about 20 percent of the rise in bowel cancer among young women, indicating other factors are contributing to the trend. The study also found that for most cancers increasing in younger adults, rates are also rising in older populations, suggesting shared underlying causes. However, ovarian and bowel cancers are exceptions, with distinct patterns in younger people. Scientists are exploring various hypotheses, including the impact of ultraprocessed foods, exposure to persistent environmental chemicals like PFAS, and disruptions to gut microbiomes caused by antibiotics. This growing incidence of cancer in younger populations is a complex issue likely driven by multiple interacting factors rather than a single cause. The findings highlight the urgent need for further research to identify these causes and inform prevention strategies, as the rising cancer burden among young adults poses significant public health challenges worldwide.