Obese women, who carry most of their
excess weight around the stomach, are 70% more likely
to develop pancreatic
cancer, research suggests.
Obesity was thought to increase the risk - but more
in men than women.
However, the new study, of more than 138,000 postmenopausal
US women over seven years, suggests it is a significant
risk factor for women too.
The study, by Sweden's Karolinska Institute, appears
in the British Journal of Cancer.
In total 251 women in the study developed pancreatic
cancer.
After taking account of other risk factors such
as smoking, the researchers calculated that the disease
was 70% more likely in women with the highest waist-to-hip
ratios - a measure of obesity.
Lead researcher Dr Juhua Luo 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."
Pancreatic cancer is the UK's sixth most common
cause of cancer death.
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.
Usually, the disease is diagnosed only once it has
spread and is difficult to treat successfully.
Only 2-3% of people survive beyond five years after
being diagnosed.
Insulin theory
The researchers believe obesity may increase the
risk of pancreatic cancer by affecting insulin levels.
Dr Luo said: "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, of the charity Cancer Research
UK, said: "Pancreatic cancer is associated with particularly
poor survival, so it is 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."
Lucie Galice, of World Cancer Research Fund, said:
"Looking at all the studies that have been done on
this subject, overall there is convincing evidence
that excess body fat increases risk of pancreatic
cancer.
"There is also convincing evidence that being overweight
increases risk of post-menopausal breast cancer, bowel
cancer and cancers of the kidney, oesophagus and endometrium.
"In fact, scientists now say that, after not smoking,
maintaining a healthy weight is the most important
thing you can do for cancer prevention."
Pancreatic cancer develops from the cells within
the pancreas, a gland located high up in the abdomen
just behind the stomach.
If pancreatic cancer is not treated, cancer cells
can spread into nearby organs or lymph nodes, or,
eventually, break away and spread to other parts of
the body.
