July 5, 2000 -- Young people don't typically have strokes, so when they do, it can be particularly frightening. We understand that older people have strokes more often than young people because the stroke risk factors, such as narrowing of the arteries, increase with age. But researchers are still trying to find out how to decrease the risk of stroke in people under 45 -- a group that doesn't typically have the risk factors of older people.
In a recent study, doctors found that stroke patients and healthy patients had similar levels of total cholesterol, but pinpointed low levels of the 'good' cholesterol, HDL, in stroke patients. HDL is believed to lower stroke risk.
The results suggest that having your HDL cholesterol measured may be a good indicator of whether you're at risk for a stroke prematurely.
High cholesterol levels that lead to artery narrowing have often been associated with an increased stroke risk. However, in this study, which was published in a recent issue of the Journal of Neurology, Neurosurgery and Psychiatry, young stroke patients were different from the typical older stroke patient because they showed no signs of narrowing of their brain arteries. This suggested that another factor was the increasing the risk.
The study involved 94 stroke patients under 45. Doctors examined the patients, questioned them about their medical histories, and studied their brain arteries with imaging techniques. They also asked whether the patients had other known risk factors for stroke, such as cigarette smoking, high blood pressure, high blood cholesterol levels, diabetes, or oral contraceptive use. Blood samples were taken and their cholesterol levels were measured. The findings were compared to a group of 111 healthy subjects.
Unlike the typical older stroke patient, only a few showed any signs of atherosclerosis, which is fatty deposits on the walls of blood vessels that narrow them, according to J.F. Albucher and colleagues at the Purpan Hospital in Toulouse, France. So having "clean" blood vessels is no guarantee that a stroke won't develop.
When the researchers measured levels of fat in the blood, they found that only a low level of HDL cholesterol was strongly associated with stroke risk. The study also confirmed that stroke risk was higher in these young patients if they had evidence of the other established risk factors for stroke, such as use of oral contraceptives (in women), smoking, and high blood pressure. Men were also more likely to have a stroke than women.
Although stroke resulting from blocked arteries in the young is a relatively rare event, Albucher suggests that doctors should be especially careful in monitoring HDL cholesterol levels in young patients, whether or not they demonstrate signs of narrowing of blood vessel walls.
Shalini Bansil, MD, a neurologist who specializes in stroke management at the Robert Wood Johnson Medical School in New Brunswick, N.J., was not surprised by the findings.
"Abnormalities in cholesterol are believed to be one of the risk factors of stroke. ... We previously just studied total cholesterol. We now know that you want the 'good cholesterol,' HDL, to be high and the 'bad cholesterol,' LDL, to be low."
Although HDL was found to be most important in this study, Bansil doesn't discount the importance of LDL. "Although the studies are not definitive, there are a lot more studies on LDL. That's what is thought of as the bigger culprit," she tells WebMD.
Bansil suggests that although narrowing of the arteries was not noticeable in most of the young stroke patients, they may still have the tendency to develop it later on. "You just can't detect the atherosclerosis because they're still young and it hasn't started to develop yet," she says.
She advises patients to have total cholesterol, as well as the subtypes of cholesterol, checked regularly. "Everyone should have these monitored, but especially if they have had a stroke." She says that if you have already had a stroke, cholesterol-lowering drugs may be appropriate to help prevent further strokes.
For more information from WebMD, visit our Diseases and Conditions Stroke page.