Re-defining future stroke risk among pre-diabetics

June 7, 2012, University of California - San Diego

Millions of pre-diabetic Americans may be at increased risk of future stroke, say researchers at the University of California, San Diego School of Medicine in a new meta-analysis of epidemiological studies, but the precise degree of that threat is confounded by differing medical definitions and factors that remain unknown or unmeasured.

"The immediate implication of our findings is that people with pre-diabetes should be aware they are at increased risk of stroke, and that this condition is frequently associated with one or more major for cardiovascular disease," said Bruce Ovbiagele, MD, a professor of neurosciences at UC San Diego School of Medicine and the study's senior author. "Beyond that, there's a great need to further refine our understanding of that risk and how it's measured."

Writing in the June 8 online edition of the , Ovbiagele and an international team of colleagues reviewed 15 qualifying prospective cohort studies that looked at the association between pre-diabetes and stroke risk. The studies, published between 2004 and 2011, involved 760,925 participants.

Pre-diabetes occurs when blood are consistently higher than normal, but not yet high enough to be diagnosed as diabetes. The condition is widespread in the United States: An estimated 35 percent of American adults – approximately 79 million people – are believed to be pre-diabetic, and thus at greater risk of developing full-blown type-2 diabetes, which afflicts roughly 26 million Americans. Diabetes is the seventh leading cause of death in the U.S., and a major risk factor for heart disease and stroke, the first and fourth leading causes of death.

People with pre-diabetes typically have the same risk factors for cardiovascular disease as people with type 2 diabetes – specifically, high blood pressure, high cholesterol levels and obesity – but the condition's effect on future stroke risk has not been established.

Ovbiagele and colleagues found that an association between future stroke risk and pre-diabetes depended upon the definition of the latter. To determine whether someone has pre-diabetes, are typically measured after a 12-hour fast. According to the 1997 American Diabetes Association (ADA), a normal fasting glucose measurement ranges between 70.2 to 100 milligrams per deciliter (mg/dL). A level between 100 and 126 mg/dL is considered pre-diabetic. A level of 126 mg/dL or above is diabetic.

By the 1997 standard, the researchers found that pre-diabetics in the studies with a fasting glucose measurement of 110 to 125 mg/dL carried a 21 percent higher chance of suffering a future stroke. Heart disease and stroke account for roughly two-thirds of all deaths among people with diabetes.

In 2003, however, the ADA redefined the fasting glucose level for pre-diabetes to 100 to 125 mg/dL. Using this less stringent definition, the researchers found no increased stroke risk for pre-diabetics. Indeed, when they analyzed three studies that provided information on participants with fasting glucose levels of 100 to 109 mg/dL they found no of stroke.

Ovbiagele said the difference in the findings suggests there may be a "threshold effect" in the relationship between fasting glucose levels and future stroke risk. "Elevated risk may only begin at or above a level of 110 mg/dL," he said.

Additional research is needed to determine the best definition predicting stroke risk among diabetics, Ovbiagele noted. It should include an assessment of more recent glycemic biomarkers, such as glycosylated hemoglobin, and be followed by randomized, controlled trials involving drugs and/or lifestyle modification to evaluate the effect of treatments on reducing the risk of future strokes.

"In the meantime, to avoid progression to or occurrence of strokes, clinicians should strongly consider recommending therapeutic lifestyle changes and maximizing the control of established factors in their patients with pre-diabetes," Ovbiagele said.

Explore further: Long-time diabetics have increased risk of stroke

Related Stories

Long-time diabetics have increased risk of stroke

March 1, 2012
The longer you have diabetes, the higher your risk for stroke, according to a study in Stroke, an American Heart Association journal.

Recommended for you

Diabetes gene found that causes low and high blood sugar levels in the same family

January 15, 2018
A study of families with rare blood sugar conditions has revealed a new gene thought to be critical in the regulation of insulin, the key hormone in diabetes.

Discovery could lead to new therapies for diabetics

January 12, 2018
New research by MDI Biological Laboratory scientist Sandra Rieger, Ph.D., and her team has demonstrated that an enzyme she had previously identified as playing a role in peripheral neuropathy induced by cancer chemotherapy ...

Enzyme shown to regulate inflammation and metabolism in fat tissue

January 11, 2018
The human body has two primary kinds of fat—white fat, which stores excess calories and is associated with obesity, and brown fat, which burns calories in order to produce heat and has garnered interest as a potential means ...

Big strides made in diabetes care

January 5, 2018
(HealthDay)—This past year was a busy, productive one for diabetes research and care.

Gene therapy restores normal blood glucose levels in mice with type 1 diabetes

January 4, 2018
Type 1 diabetes is a chronic disease in which the immune system attacks and destroys insulin-producing beta cells in the pancreas, resulting in high blood levels of glucose. A study published January 4th in Cell Stem Cell ...

Goodbye, needles? Patch might be the future for blood-sugar tracking

January 4, 2018
(HealthDay)—Developers of a new patch hope to eliminate a big barrier in type 2 diabetes treatment—painful finger-sticks and injections. The new patch—which actually uses an array of tiny needles that researchers promise ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.