Being overweight over a lifetime doubles a woman’s risk of developing uterine cancer. That’s according to a Cancer Research UK-funded study published today in BMC Medicine. The study from the University of Bristol is one of the first to find that for every 5 extra units of body mass index, a woman’s risk of developing uterine cancer doubles – an increase of 88%. This result is higher than most previous studies suggest and reflects the influence of body weight throughout life. Five units of body mass index is the difference between the “overweight” category and the “obese” category. The international study looked at genetic samples from about 120,000 women from Australia, Belgium, Germany, Poland, Sweden, the United Kingdom and the United States, of whom about 13,000 had uterine cancer. This large statistical analysis is one of the first studies of its kind to look at the effect of a higher lifetime body mass index on the risk of developing uterine cancer. The researchers examined markers for 14 characteristics that may link obesity and uterine cancer. They found two hormones – fasting insulin and testosterone – that increase the risk of developing uterine cancer. By determining exactly how obesity increases the risk of developing cancer, for example through hormones, scientists may in the future use therapeutics to reduce or increase their levels in individuals who are at higher risk. For example, drugs such as metformin, used to treat diabetes, can reduce hormone levels, and research suggests that this drug also affects cancer risk, although further studies are ongoing. Uterine cancer is one of the cancers most closely associated with obesity. Overweight and obesity are the second most preventable causes of uterine cancer. The study is an interesting first step toward how genetic analyzes can be used to uncover exactly how obesity causes cancer and what can be done to address it. The links between obesity and uterine cancer are well known, but this is one of the largest studies to examine it at the molecular level. More research is needed to examine exactly which treatments and medications can be used to manage cancer risk among people struggling with obesity. We now know that being overweight and obese increases the risk of developing 13 different types of cancer. To reduce the risk of cancer, it is important to maintain a healthy weight through regular physical activity and a balanced diet. References: https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-022-02322-3