Insulin
Resistance Double Trouble For Some Diabetics
Blood Sugar Control
May Not Prevent Heart Disease In Type 1 Diabetes
Blood sugar control
may have little influence over the development of heart disease
in people with type 1 diabetes, a new study says.
Instead, researchers
say insulin resistance - the hallmark of type 2 diabetes - is
a better indicator of who is going to get heart disease among
people with type 1 diabetes.
"We suspect that insulin
resistance occurs in those with type 1 diabetes in the same
way as it does those with type 2, essentially giving these individuals
'double diabetes' and greatly increasing their risk of heart
disease," says Dr. Trevor Orchard, acting chairman of the department
of epidemiology at the University of Pittsburgh Graduate School
of Public Health.
The study results
appears in a new report in Diabetes Care.
Study Gives
Insights into Type 1
For type 1 diabetics,
this may come as good news. It might mean that some type 1 diabetics,
at least those without insulin resistance, are at lower risk
of heart disease than previously believed, Dr. Orchard says.
And while those with
insulin resistance may be at higher risk, medications and lifestyle
changes can boost the body's ability to use insulin.
Type 1 and type 2
diabetes are, in many ways, very different diseases, Dr. Orchard
says.
Type 1, most often
thought of as a disease that strikes in childhood, occurs when
the body attacks and destroys its own insulin-producing beta
cells. Insulin is responsible for helping tissues use glucose,
the body's energy source.
Type 1 diabetes, the
less common form of the illness, accounts for 5 percent to 10
percent of the 17 million people in the US with diabetes, according
to the American Diabetes Association (ADA).
Type 1 diabetics need daily insulin injections to survive.
In type 2 diabetes,
the pancreas is usually still producing insulin, but the cells
of the liver, muscles, and fatty tissues develop a resistance
to it. Type 2 can often be controlled with weight loss, diet,
and exercise.
Physicians have
known for a while that people with diabetes are at higher risk
of heart disease, but most of the research has been done in
type 2 diabetics, says Dr. Nathaniel Clark, national vice president
of clinical affairs for the ADA.
"The question keeps
coming up: 'What about type 1 diabetics?'" Dr. Clark says. "There
have been very few studies that have shown the risk factors
for people with type 1."
Insulin Resistance
a Major Factor
When trying to help
diabetics control their risk of heart disease, physicians
tend to focus on three risk factors: blood sugar, blood pressure,
and cholesterol. But it is unknown which is the most significant
factor, or if, perhaps, one factor matters more or less in type
1 or 2 diabetes, Dr. Clark says.
Dr. Orchard's study
begins to address that, he says.
"I think the most
important finding is that these researchers looked at the traditional
risk factors, and what they found was that blood sugar wasn't
terribly helpful in predicting who gets heart disease," Dr.
Clark says. "There were other factors that were much more important."
Namely, insulin resistance
was found to be a significant factor.
Dr. Orchard and his
colleagues examined 658 type 1 diabetics, ages 6 to 40, every
two years for a 10-year-period. During that time, there were
108 cardiovascular events, including angina and heart attacks.
Researchers then took
a subset of 24 patients and measured their insulin resistance
using a type of testing that is considered the gold standard.
The problem with this test is that it is time-consuming - patients
have to stay overnight in the hospital - and expensive.
As a result, Dr.
Orchard developed a surrogate test for insulin resistance using
data about the patients' waist-to-hip ratio, blood pressure,
and long-term blood sugar levels.
They found that type
1 diabetics with the highest levels of insulin resistance based
on these calculations were the most likely to have a cardiovascular
event.
Always consult your
physician for more information.
Online
Resources
(Our Organization
is not responsible for the content of Internet sites.)
American
College of Physicians
American
Diabetes Association
American
Heart Association
Diabetes
Care
National
Institutes of Health (NIH)
|
June 2003
Insulin
Resistance Double Trouble For Some Diabetics
Study Gives
Insights into Type 1
Insulin
Resistance a Major Factor
What
Is Diabetes?
How
Does Diabetes Affect Blood Glucose?
How
Do the Three Main Types of Diabetes Differ?
Online
Resources
What
Is Diabetes?
Diabetes is a metabolic
disorder characterized by a failure to secrete enough insulin,
or, in some cases, the cells do not respond appropriately to
the insulin that is produced.
Because insulin is
needed by the body to convert glucose into energy, these failures
result in abnormally high levels of glucose accumulating in
the blood.
Diabetes may be a
result of other conditions such as genetic syndromes, chemicals,
drugs, malnutrition, infections, viruses, or other illnesses.
The three main types
of diabetes - type 1, type 2, and gestational - are all defined
as metabolic disorders that affect the way the body metabolizes,
or uses, digested food to make glucose, the main source of fuel
for the body.
How
Does Diabetes Affect Blood Glucose?
For glucose to be
able to move into the cells of the body, the hormone insulin
must be present. Insulin is produced primarily in the pancreas,
and, normally, is readily available to move glucose into the
cells.
However, in persons
with diabetes, either the pancreas produces too little or no
insulin, or the cells do not respond to the insulin that is
produced. This causes a build-up of glucose in the blood, which
passes into the urine where it is eventually eliminated, leaving
the body without its main source of fuel.
How
Do the Three Main Types of Diabetes Differ?
Although the three
main types of diabetes are similar in the build-up of blood
glucose due to problems with insulin, there are differences
in cause and treatment:
type 1 diabetes
Type 1 diabetes is an autoimmune disease in which the body's
immune system destroy the cells in the pancreas that produce
insulin, resulting in no or a low amount of insulin. People
with type 1 diabetes must take insulin daily in order to live.
type 2 diabetes
Type 2 diabetes is a result of the body's inability to make
enough, or to properly use, insulin. Type 2 diabetes may be
controlled with diet, exercise, and weight loss, or may require
oral medications and/or insulin injections.
gestational
diabetes
Gestational diabetes occurs in pregnant women who have not had
diagnosed diabetes in the past. It results in the inability
to use the insulin that is present and usually disappears after
delivery. Gestational diabetes may be controlled with diet,
exercise, and attention to weight gain. Women with gestational
diabetes may be at higher risk for type 2 diabetes later in
life.
Always consult your physician for more information.
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