The obesity epidemic is
definitely driving the type 2 diabetes epidemic,
says a new study by the U.S. Centers for Disease
Control and Prevention.
While other factors play some role in the
rapidly increasing number of people with diabetes,
obesity is the major factor in the trend, said Linda
S. Geiss, lead author of the study, published in
the May issue of the
American Journal of Preventive
Medicine.
The study, based on concrete numbers drawn from
the entire country, backs up what experts have long
believed, said Geiss, a statistician with the
CDC's Division of Diabetes Translation.
"Most incidence studies [of diabetes] have
been done on samples that aren't representative
of the United States," she said. "These
[new] data are nationally representative. And these
data certainly help make the case that obesity is
a major factor in the diabetes epidemic. I think
it adds to the evidence."
Geiss and her research team looked at statistics
from the National Health Interview Survey, an ongoing
nationwide in-person survey of about 40,000 households.
They zeroed in on the years 1997 to 2003 to look
for trends in the incidence of diagnosed diabetes
in adults aged 18 to 79. Each year, about 31,000
adults were asked whether a health professional
had told them they had diabetes. Not included was
gestational diabetes, a type that occurs during
pregnancy.
Participants were asked how old they were when
their diabetes was diagnosed. The researchers had
access to information about height and weight so
they could compute the participants' body mass index
(BMI, a ratio of height to weight). A BMI of 25
and above is termed overweight; 30 and higher is
considered obese.
Excess weight and inactivity are risk factors for
type 2 diabetes, in which the body doesn't properly
use the hormone insulin, which is crucial for converting
sugars and starches in the blood into fuel for the
body.
The incidence of diagnosed diabetes rose 41 percent
from 1997 to 2003 among the study participants,
Geiss found.
About 20 million Americans have diabetes, although
many do not yet know it, according to the American
Diabetes Association.
About two-thirds of American adults are now overweight
or obese, according to the
National Institutes of Health. In 1960, 13
percent of adults were obese, but by 2000, nearly
31 percent were.
Geiss wanted to determine, however, if the rise
in diabetes might be due at least partially to better
detection methods allowing for earlier diagnosis.
"If we were doing a better job, we would be
detecting it earlier and when people are healthier."
But from 1997 to 2003, those diagnosed with diabetes
were not healthier or younger. Increased detection
of diabetes "could be part of the answer,"
she said, "but not the whole answer. It doesn't
seem to be a major factor. Most of the increase
in diabetes occurred in those with a BMI of 30 or
above. In 2003, 59 percent of the newly diagnosed
were at a BMI of 30 or above. Another 30 percent
were overweight, with a BMI of 25 to under 30. All
together, 89 percent of the [new] cases were either
overweight or obese."
The study findings will not surprise experts, said
Mary Austin, a diabetes educator and a researcher
at Henry Ford Health System in Detroit, and part
of the ACCORD (Action to Control Cardiovascular
Risk in Diabetes) study.
"These findings are very reflective of what
we see around the world," Austin said. "The
rise in weight and obesity is being seen globally,"
she said, and with it, more type 2 diabetes is being
diagnosed.
Her Advice? Know your risks and do something about
them. "If you are not at your ideal body weight
and are not active, over time, you have a risk of
diabetes," Austin said.
The oft-repeated message holds here, she said.
Keep your weight at a healthy level and get regular,
moderate exercise.
Geiss added: "Recent studies have shown we
can prevent diabetes in those with risk factors,
just with moderate lifestyle changes. Those include
cutting down on daily calories for weight loss,
if necessary, and getting activity into each day."
