Obesity could be causing as many as one in ten cancer cases across Europe — a figure far higher than the 2% to 8% previously estimated by researchers, according to a study published today by the German Cancer Research Center. The findings suggest up to 11.5% of cancers may be attributable to being overweight, with abdominal fat emerging as a particularly dangerous factor, especially among women.
The research, led by epidemiologist Hermann Brenner, used data from 458,543 women and men tracked through the UK Biobank, one of the world's largest health datasets. Participants were followed for an average of 12 years, during which 50,000 new cancer cases were identified. The study's methodology marks a departure from earlier work that relied solely on body mass index, or BMI, which doesn't distinguish between fat and muscle mass and fails to show how fat is distributed in the body.
Why Abdominal Fat Matters
Michael Leitzmann, an epidemiologist at the University of Regensburg who wasn't involved in the study, said the DKFZ researchers "have not only updated existing risk estimates, but have also questioned whether the link between excess weight and cancer may have been underestimated until now." He said fat around the abdomen isn't just a passive store of excess calories. "They trigger what is known as a chronic inflammatory metabolic state," he said.
Leitzmann explained that excess abdominal fat functions like a gland that releases signaling molecules known as adipokines, which travel through the bloodstream and influence cell growth, cell division and the inhibition of programmed cell death. "These are all mechanisms that can contribute to the development and subsequent growth of tumors," he said. The DKFZ researchers focused not only on BMI but also on waist circumference and the waist-to-hip ratio, providing a more nuanced picture of obesity's health impact.
Higher Risk for Women
The study suggests that the proportion of overweight women who develop cancer is higher than that of men, though Leitzmann urged caution and said further studies with a similar design are needed to see whether the results can be replicated. He said being overweight is blamed, among other things, for breast, uterine and ovarian cancers, which are hormone-dependent. Estrogen can stimulate the growth of breast cancer and excess abdominal fat can contribute to elevated estrogen levels, he said.
The researchers also tried to rule out a bias in previous studies by excluding the first few years after enrollment, since cancer can cause weight loss before diagnosis. Only cancer cases that occurred seven years after the start of the observation period were considered, and that made the statistical link between being overweight and cancer clearer.
Public Health Implications
Leitzmann said most people are now aware that obesity increases the risk of cardiovascular disease or Type 2 diabetes, and that losing weight also reduces the risk of heart attacks, strokes and diabetes. He added, "To me, this clearly indicates that, by preventing obesity, we will be able to make a greater contribution to cancer prevention than previously assumed."
Why This Matters:
If obesity is responsible for more than one in ten cancer cases, European healthcare systems face mounting fiscal pressure from preventable disease. Cancer treatment is among the most expensive categories of medical care, and rising obesity rates — particularly among younger Europeans — suggest costs will continue climbing. The study's focus on abdominal fat distribution rather than BMI alone could reshape public health guidance and screening protocols across member states. For national governments already struggling with healthcare budgets, the findings underscore the economic case for prevention programmes targeting obesity before it becomes a cancer risk. The gender disparity revealed in the data — with women facing higher cancer risk from excess weight — also raises questions about whether current prevention strategies are adequately tailored to physiological differences.