Anyone can have a stroke--thousands of people in the U.S. die or suffer a disabling brain injury from stroke every year. The odds of whether you will be one of them increase dramatically if you have hypertension, diabetes or smoke.
The tragedy is that these big three risk factors are often--and in the case of tobacco, totally--preventable.
In the past, clinicians simply did their best to manage risks. Current thinking is now shifting to a more proactive approach.
"The big push is in primordial prevention. Rather than waiting and trying to manage risks as they develop, the focus is on going upstream to prevent them," UAB researcher George Howard, PhD, said.
Howard is co-principal investigator of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study of more than 30,000 volunteers 45 or older in 48 states aimed at understanding why African-Americans and southerners are more likely to have a stroke.
"Though prevention tends to be associated with younger and middle aged patients, one of the things we are learning from our REGARDS study is that continuing efforts to prevent risk factors for stroke is also an important part of caring for seniors," Howard said.
"By the time people in the U.S. are 65, about half of Caucasians and 70 percent of African Americans have hypertension. However, at that age many people still have a normal blood pressure and show no sign of diabetes and other risk factors, but they may develop them if they let down their guard and aren't encouraged to continue working to stay healthy."
Preventing risk factors for stroke is especially important in the African-American population, which not only tends to have higher rates of strokes at all ages and higher rates of hypertension, but also tend to suffer greater health effects as their blood pressure rises than others who have the same increase.
"In research, one of the things I find particularly satisfying is finding out that I'm wrong," Howard said. "When the study began, I assumed the racial disparity in hypertension might come from the economic effects in poorer neighborhoods, either from a lack of education and awareness of hypertension or from the cost of treatment. What I found was the opposite. African-Americans seem to have a high level of awareness of hypertension and many are being treated, but they simply aren't responding with the results we'd like to see.
"One of the problems may be that they aren't getting the right medication. We are finding that African-Americans tend to be more sensitive to salt. Many should be on diuretics, but aren't. Diuretics are effective, inexpensive and should be considered early in treatment."
However, neighborhoods do seem to have an effect on stroke risk. African-Americans in more affluent areas tend to be less at risk than those who live in poorer neighborhoods. Whether that difference comes from stress, economic and social effects on diet, other influences or a combination of factors is now under study, as are disparities among people in different occupations. More than 300 papers have come out of the REGARDS study, and publication of findings related to these topics is anticipated in the coming year.
The effect of diet on type 2 diabetes and obesity is also a major factor in stroke risk as well as a wide range of other disorders. In addition to cancer, emphysema and heart disease, smoking can kill by increasing the risk for stroke. Rates of tobacco use are also higher in poorer economic groups.
Neurologist Toby Gropen, MD, director of the Division of Cerebrovascular Disease and head of the UAB Comprehensive Stroke Research Center, agrees that preventing a stroke by preventing the development of risk factors is worth the effort. This is especially true considering the challenge of undoing the damage after a stroke happens.
"We can do wonderful things with physical therapy and occupational therapy. When we have stabilized the patient, we aggressively focus on preventing a second stroke, which is often associated with more morbidity and disability" Gropen said. "However, it's much better not to have a stroke at all. If you do, recognizing what's happening and getting help quickly can make a tremendous difference in limiting damage.
"Timing is critical. If we can get the patient to a hospital and administer TPA as soon as possible, we can often minimize the damage to the brain. We only have a window of about four and a half hours, and the earlier, the better."
Another factor that can make a tremendous difference is getting to a medical center with a neuro ICU and a team experienced in using a catheter procedure to actually remove a clot or debris blocking blood flow in the brain.
"We can insert a catheter near the groin and guide it up through the body and into the area of the brain where there is a blockage. Then we can pull out the clot to reestablish blood flow," Gropen said.
"Of course, all this depends on getting the patient to the right place quickly. We're fortunate to have a very good emergency medical system in Birmingham. People who think they may be having a stroke should know to call 911 and not wait. They should also know the FACE mnemonic to help them recognize when they need to get help--Facial drooping, Arm weakness, Speech difficulties, and Time."
Strokes tend to happen more often in older people, and in addition to the risk factors they may have acquired in middle age, some may face additional risks if they have atrial fibrillation or blockages in the neck.
"Atrial fibrillation can cause clots, and we need to do what we can to control or prevent it. Although stents can help with blockages in the neck, we try to avoid them if possible, because the risk of stroke during surgery is higher in older patients. Their vessels tend to be more calcified and plaques are more likely to break off and release debris into the bloodstream," Gropen said.
Gropen is optimistic about new treatments that should improve outcomes for stroke patients in the future.
"Within the next few months, we will begin an NIH study to see if we can extend the window for acute treatment, especially for the catheter procedure, by using imaging in a clinical trial," Gropen said. "Exciting things are also happening with stem cells. In the not so distant future, we hope to be able to implant stem cells to repair damaged areas of the brain."
George Howard, PhD
Stroke, hypertension, diabetes, smoking, REGARDS, George Howard PHD, Toby Gropen MD, UAB