Diabetes Forecast

Spotting a Stroke Fast Minimizes Damage

By Erika Gebel Berg, PhD ,

Here's something to celebrate: The Centers for Disease Control and Prevention announced last year that between 1997 and 2006, the death rate from strokes and heart attacks dropped by 40 percent among people with diabetes. Most of the credit goes to you. People with diabetes are getting better at controlling the disease's risk factors and preventing complications.

Strokes may get less attention than heart attacks, but people with diabetes should be on guard against these "brain attacks," too. Compared to people without diabetes, they are at least twice as likely to have a stroke. But the recent gains in health for people with diabetes demonstrate that strokes are highly preventable, if you know what to do.

Vulnerable Vessels

There are two main types of stroke: hemorrhagic and ischemic. Hemorrhagic strokes, the less common type, are caused by the rupture of a blood vessel in the brain, while ischemic strokes are triggered by a clot that gets stuck in a blood vessel. The common thread is that all strokes interrupt the blood supply to the brain, which can cause serious damage. Ischemic strokes are the "most relevant type for people with diabetes," says Jane Khoury, PhD, associate professor at the University of Cincinnati. Studies suggest that diabetes increases the risk of ischemic but not hemorrhagic strokes.

Why does diabetes raise ischemic stroke risk? That's not entirely clear, but Trevor Orchard, MD, MMedSci, FAHA, FACE, a professor at the University of Pittsburgh, thinks "it is probably related to the atherosclerosis." This condition, which is common in people with diabetes, is caused by plaque, a buildup of fat, cholesterol, calcium, and other substances on the inside walls of arteries. When plaque breaks apart, it releases materials that cause blood to congeal, forming a clot.

Ischemic strokes are caused either by blood clots that form directly in the brain or by clots that originate elsewhere in the body and travel to the brain. The heart is a significant source of clots that end up in the brain, says Orchard, because the brain is the first stop after blood leaves the heart. This is a special concern, he says, in people with atrial fibrillation, a condition characterized by an irregular heartbeat. "When the chambers of the heart aren't contracting smoothly and fully, the blood sits and isn't moved normally," says Orchard. That promotes clot formation.

Strokes are commonly thought of as an older-adult problem, and risk does go up after age 55, but a recent study by Khoury suggests that younger people with diabetes have reason to be concerned, too. "In 2005, the incidence of stroke was going down," she says, but "stroke in the younger population was going up." The study, published in the journal Stroke in April, found that people under 65 with diabetes are 12 times as likely to have a stroke as people the same age without the disease, compared with just a two to three times greater risk in older people. Khoury says that the reason may be that as people without diabetes age, they accumulate additional risk factors for stroke. The study also shows, she says, how important it is for everyone with diabetes to be aware of and control stroke risk factors.

Prevent and Persevere

The risk factors for stroke are like those for heart attacks; both conditions are associated with cardiovascular disease. Genetics can elevate the threat of stroke, but the good news is that other risk factors are within your control. "Stroke is preventable," says Mary Cushman, MD, MSc, a professor at the University of Vermont College of Medicine, who assessed the impact of seven modifiable factors—exercise, cholesterol, diet, blood pressure, weight, blood glucose, and smoking—on stroke. "These behavioral and lifestyle factors are important in stroke," she says, according to many studies.

In her study, Cushman scored participants, who were 45 and older, according to their health behaviors and measures, giving zero points for a trait associated with poor health (smoking or obesity, for example), one point for a middle-of-the-road characteristic (having quit smoking less than a year ago or being overweight), and two points for an "ideal" trait (being a nonsmoker or of normal weight). Of 5,000 people in the study, only two got a perfect score, she says, so virtually everyone has room for improvement.

The results, published in June in Stroke, showed that even small changes in lifestyle can have a big impact on stroke risk. For each point increase in score, a person had an 8 percent lower risk of having a stroke over the next five years. For people with diabetes, good blood glucose control boosted scores. The key for people with diabetes, says Cushman, is to keep blood glucose in check and control other risk factors.

But not all risk factors are equal. "The primary predictor of stroke, with or without diabetes, is high blood pressure," says Orchard. "Good blood pressure control is critical." While exercise and healthy eating can bring blood pressure down, the American Diabetes Association (ADA) supports the "prompt initiation" of medication along with lifestyle changes in people with diabetes who have hypertension. The ADA recommends that people with diabetes maintain a blood pressure of 140/80 mmHg, though lower systolic pressures (the top number) may be appropriate for some patients. This guideline is based on research that primarily focuses on type 2 diabetes. "What we really don't know is what the ideal target is for type 1," says Orchard. "We don't have good data for type 1 diabetes."

Strokes can occur suddenly, but knowing the signs can ensure prompt treatment ("Stroke Signals," right). If the symptoms quickly disappear, the condition may be a transient ischemic attack (TIA) or ministroke. In this situation, the clot unblocks itself. While these ministrokes may not do any direct damage—whether they do is a matter of debate among researchers—TIAs greatly increase a person's risk for a subsequent stroke.

A doctor can diagnose a stroke based on visible changes, such as a droop on one side of the face, or the results of brain scans. If an ischemic stroke is diagnosed within three hours, a doctor can usually administer a drug that will dissolve the clot. (The treatment would be different for a hemorrhagic stroke.) "Speed is of the essence," says Khoury. In some situations, surgery may also come to the rescue of a stroke victim. A surgeon can prop open an artery with a stent or directly remove blockages in arteries leading to the brain. Doctors are getting better and better at saving people from the worst that strokes can do. But prevention is best, and that's up to you.

Stroke Signals

If you or someone you love has the following symptoms, it may be a sign of stroke and time to call 911. To prevent brain damage, seek help immediately; some stroke treatments are time sensitive.

  • Weakness or numbness on one side of the body
  • Sudden confusion or trouble understanding
  • Trouble talking
  • Dizziness, loss of balance, or difficulty walking
  • Trouble seeing out of one or both eyes
  • Double vision
  • Severe headache

Source: The American Diabetes Association



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