SUNDAY, April 3 (HealthDay News) -- Diabetes is already linked
to a number of complications, but emerging evidence suggests an
increased risk of cancer can be added to that list.
A new study found that women with diabetes had an 8 percent
increased risk of developing cancer generally, while men with
diabetes had a 9 percent higher risk when rates of prostate cancer
were excluded from the calculation.
The risk of dying from a cancer was also higher in people with
diabetes -- 11 percent greater for women and 17 percent higher in
"We used a prospective cohort to evaluate the relationship between diabetes and cancer risk," said the study's lead author, Gabriel Lai, a cancer prevention fellow at the U.S. National Cancer Institute. "Diabetes was associated with an 8 percent increase in cancer risk in women, and there was a similar pattern in men, except for prostate cancer," said Lai.
For reasons that remain unclear, diabetes was actually
associated with a
lower incidence of prostate cancer in men, the study found.
When rates of prostate cancer were included in the mix, diabetic
men's odds for cancer generally were reduced by 4 percent.
But once the statistics on prostate tumors were factored out,
men with diabetes were found to have a 9 percent higher risk for
cancer overall, compared to nondiabetic men.
Lai is scheduled to present the study's findings on Sunday at
the American Association for Cancer Research meeting in Orlando,
Fla. Research presented at meetings is considered preliminary until
it is published in a peer-reviewed journal.
The study included data from the National Institutes of
Health-AARP Diet and Health Study that included 295,287 men and
199,665 women from eight states (California, Florida, Georgia,
Louisiana, Michigan, North Carolina, New Jersey and
Diabetes was self-reported by the study participants, but they
didn't note whether or not they had type 1 or type 2 diabetes.
However, Lai said that in this population, the majority would have
type 2, the more common form. The researchers also were unable to
evaluate diabetes management or different medications, as this data
wasn't included in the initial study.
After 11 years of follow-up, 55,888 men and 26,364 women had
The risk of liver cancer was increased more than two-fold in
people with diabetes, according to the study. The risk of cancer of
the rectum was increased by 28 percent in people with diabetes, and
the risk of colon cancer was increased by 15 percent.
In men, the risk of pancreatic and bladder cancers was increased
in those with diabetes. In women, stomach, anus and uterine cancer
risk was greater in those with diabetes.
No association was found between lung, skin and other cancers
and diabetes in this study.
Lai said it's not clear what the mechanism behind these
increased risks might be, but said there are numerous
possibilities. "It's important that more studies are done," he
Dr. Joel Zonszein, director of the clinical diabetes center at
Montefiore Medical Center in New York City, agreed that there could
be many causes. "There are so many risk factors for cancer. Is it
the way they eat, inactivity, socioeconomics? We really don't know
what the cause is," he said.
But, he added, "Those with diabetes need to be aware that they
are at a higher risk of certain cancers, and they have to be
screening for cancer. Also, modifiable risk factors, like smoking,
should be stopped."
Lai recommended lifestyle modifications, such as eating a
healthful diet and exercising, to prevent diabetes and cancer.
"There are a lot of risk factors that are very similar among the
two diseases. Maybe avoiding diabetes may be even better for
avoiding cancer risk. In general, there are a number of benefits in
avoiding diabetes, including the possibility of reducing morbidity
and mortality in cancer," he said.
Another study, also scheduled for presentation at the AACR
meeting, linked metabolic syndrome to an increased risk of liver
cancer. Someone with metabolic syndrome has three or more of the
following conditions: high blood pressure, elevated waist
circumference, high triglycerides, increased fasting blood sugar
levels and low HDL (good) cholesterol levels.
People with this condition are known to have an increased risk
of heart disease, but the current study, which analyzed more than
4,000 people with liver cancer and compared them to nearly 200,000
people without cancer, found that people with metabolic syndrome
were even more likely to develop liver cancer.
The study found that 37.1 percent of people with a type of liver
cancer called hepatocellular carcinoma had metabolic syndrome,
while only 17.1 percent of those without liver cancer had metabolic
syndrome. Nearly 30 percent of people with another type of liver
cancer called intrahepatic carcinoma had metabolic syndrome.
Learn more about steps you can take to help prevent cancer from
U.S. National Cancer Institute.