Obesity 'hikes up' pancreatic cancer risk in women

Obese women, who carry most of their excess weight around the stomach, are 70 per cent more likely to develop pancreatic cancer, according to a study published online in the British Journal of Cancer.

A team of researchers followed more than 138,000 postmenopausal women in America for over seven years to investigate the effects of obesity on pancreatic cancer as a part of the Women's Health Initiative - an ongoing study focussing on health problems experienced by postmenopausal women.

251 women in the study developed pancreatic cancer. Of these, 78 women had the highest waist-to-hip ratios. This is 70 per cent more than the 34 women with the lowest waist-to-hip ratios who went on to develop the disease - after adjusting for other potential risk factors including age and smoking status.

Lead author Dr Juhua Luo, based at the Karolinska Institute in Sweden, said: "We found that the risk of developing pancreatic cancer was significantly raised in obese postmenopausal women who carry most of their excess weight around the stomach. Obesity is a growing and largely preventable problem, so it's important that women are aware of this major increase in risk."

In 2004, around 7,400 cases of pancreatic cancer were diagnosed in the UK, and there are around 7,000 deaths from the disease each year. Around 3,800 women were diagnosed with pancreatic cancer in 2004 in the UK.

Pancreatic cancer is the UK's sixth most common cause of cancer death. Usually, the disease is diagnosed only once it has spread and is difficult to treat successfully. Only two or three per cent of people survive beyond five years after being diagnosed.

Before now, the most well established risk factors for pancreatic cancer were smoking and chronic pancreatitis - a rare inherited condition. Obesity was thought to play a role but the evidence pointed to a slightly stronger risk increase in men than women. This new research strengthens the evidence linking obesity to pancreatic cancer risk in women.

Research has also suggested that diabetes and abnormal insulin levels may play a role. The authors of this study believe that obesity could increase the risk of pancreatic cancer by affecting insulin levels.

Dr Luo continued: "We know that carrying a high proportion of abdominal fat is associated with increased levels of insulin, so we think this may cause the link between obesity and pancreatic cancer."

Dr Lesley Walker, director of cancer information at Cancer Research UK, said: "Pancreatic cancer is associated with particularly poor survival, so it's crucial that we learn more about how to prevent the disease.

"About a quarter of all cancer deaths are caused by unhealthy diets and obesity and it's important that people are aware of this risk."

*J Luo et al. Obesity and risk of pancreatic cancer among postmenopausal women: the Women's Health Initiative (United States). British Journal of Cancer; advance online publication, July 15, 2008; doi: 10.1038/sj.bjc.6604487.