Study: Obesity 'bigger cancer risk' than previously thought
A new study has found that being significantly overweight could be responsible for more cases of cancer than previously known. Abdominal fat, in particular, increases
A new study has found that being significantly overweight could be responsible for more cases of cancer than previously known. Abdominal fat, in particular, increases the risk of cancer — especially among women. Being overweight or obese significantly increases the risk of developing colon cancer, breast cancer or liver cancer, and is a major risk factor for 10 other types of cancer, a new study has found. Until recently, researchers believed that 2% to 8% of all cancer cases were attributable to excess body weight. But a new study by a team led by Hermann Brenner, an epidemiologist with the German Cancer Research Center (DKFZ), suggests that this was a serious underestimate. According to the study, up to 11.5% of cancers may be attributable to being overweight. 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," Michael Leitzmann, an epidemiologist at the University of Regensburg, told DW. Leitzmann, who was not involved in the study, researches diet, body weight, physical activity and the development of chronic diseases at the university's Institute of Epidemiology and Prevention, and has advised German Cancer Aid.
The abdominal-fat 'trigger' The DKFZ team changed its research methods for the new study. Previous research used body mass index (BMI), which is calculated based on height and weight, as an indicator of excess weight. But BMI does not distinguish between fat and muscle mass, and does not provide information on how fat is distributed throughout the body. This is important, because not all fat is the same. Fat cells that accumulate around the abdomen are more than just a passive store for excess calories, unlike those in other parts of the body. "They trigger what is known as a chronic inflammatory metabolic state," Leitzmann said. Excess abdominal fat functions like a gland that releases various signaling molecules, known as adipokines. These travel through the bloodstream to different parts of the body, where they influence other metabolic processes — including cell growth and division, as well as the inhibition of programmed cell death. "These are all mechanisms that can contribute to the development and subsequent growth of tumors," Leitzmann said. The DKFZ researchers therefore focused not only on BMI but also on waist circumference and the waist-to-hip ratio. Data from 458,543 women and men from the UK Biobank, which holds one of the world's biggest health datasets, were included in the study.
The BriefWire