May Raise Cancer Risk
Shows Liver, Kidney, and Pancreatic Cancers More Frequent in Diabetes
Sept. 25, 2006 -
Adults with diabetes may be at
increased risk for developing several kinds of cancer, according to
new research from Japan.
In the study, men with diabetes were found to
have more liver, kidney, and pancreatic cancers than men without the
disease. And women with diabetes had more stomach and liver cancers
than women who didn't have diabetes.
The Japanese study presents some of the
strongest evidence yet linking diabetes and cancer, but it is not yet
clear if diabetes actually causes malignant disease, researchers from
the National Cancer Center, Tokyo, wrote.
Diabetes Rates on the Rise
As with other industrialized countries,
including the U.S., diabetes rates have skyrocketed in Japan in recent
years, and they continue to rise.
Approximately 150 million people worldwide
have diabetes. But that number is expected to double within the next
two decades as the population ages.
"The remarkable increase in the
diagnosis of diabetes in Japan in recent years may affect future
trends in the incidence and type of cancer," the Japanese
researchers write in the Sept. 25 issue of the Archives of
Researcher Manami Inoue, MD, PhD, and
colleagues followed nearly 98,000 men and women in Japan for 9 to 13
years. Participants were between the ages of 40 and 69 when they
entered the study.
At enrollment, 3,097 of the men (6.7%) and
1,571 of the women (3.1%) had diabetes or had a history of having the
disease. By the end of the study's follow-up in December 2003, 3,907
men, including 366 with diabetes, and 2,555 women, including 104 with
diabetes, had developed cancer.
Total cancer risk was found to be 27% higher
for men with diabetes than for men without the disease. For women with
diabetes, they found an increased risk for stomach and liver cancers
Among men, the risk was especially high for
cancers of the liver, kidney, and pancreas.
The Role of Obesity
Obesity is one of the biggest risk factors
for type 2 diabetes; it is also a well-established risk factor for
certain cancers, including those of the colon, endometrium (inner
lining of the uterus), breast, kidney, and esophagus.
But evidence from this and earlier studies
suggests that being overweight alone may not fully explain the
increase in cancers among diabetes patients.
In a study reported last year that included
more than 1 million South Koreans, having diabetes was associated with
a 30% increase in risk for dying from cancer
, even though few of the study participants were
The highest risk was for cancer of the
pancreas -- the organ in the body that produces blood-
It has been suggested that excess insulin in
people with type 2 diabetes may promote the growth of pancreatic and
Eugenia Calle, PhD, the American Cancer
Society director of analytic epidemiology, tells WebMD that the link
between diabetes and certain cancers has been well established over
"I would say that there is little
question that diabetes is an independent risk factor for cancers of
the liver, pancreas, colon, and kidney and for endometrial
cancer," she says.
American Diabetes Association president Larry
Deeb, MD, tells WebMD that the new findings add to the evidence that
people who take steps to lower their risk of developing type 2
diabetes or control the disease once they have it may also be lowering
their cancer risk.
That means eating right and getting plenty of
exercise, he adds.
"Preventing diabetes can certainly lower
your cardiovascular risk, and it appears that the same is true for
certain cancers," he says.