Factors in getting a Stroke

Strokes are generally brain infarcts, in which a piece of plaque breaks off from the carotid artery, travels to a portion of the brain and causes a stroke. The other cause of thrombotic stroke is when the carotid artery gets a clot within it and blocks the arterial supply to an entire hemisphere of the brain, causing a large stroke.

It was once believed that when the LDL cholesterol is increased, it is a predictor of stroke. Other blood lipids, however, seem by research to be more predictive of those who get a stroke. These are the triglycerides. A recent study, published in “Stroke” looked at almost 800 middle aged to older women who had a stroke over an eight year period of time. They were age and race-matched with another woman who didn’t have a stroke.

Of the top one fourth of women with the highest triglycerides, these women had 56 percent more likely to suffer from a stroke than the bottom one fourth of women with the lowest triglycerides. The link between triglycerides and strokes held even when the researchers accounted for high blood pressure and diabetes, other risk factors for heart disease.

The American Heart Association also recognizes the risk of stroke with those who have high triglycerides. An acceptable level of triglycerides is considered to be less than 200 mg/dL. Those with triglycerides higher than 200 mg/dL are considered to be too high and to put a person at risk for triglycerides.

LDL cholesterol, in this study, was not considered to be a risk factor for stroke; however IDL or intermediate-density lipoproteins did put a person at a greater risk for heart disease. Those with the most IDL had a 46 percent greater risk of stroke than those who had low IDL levels.

The same was true with VLDL or very low density lipoproteins. Those high VLDL risk factors had a higher than normal stroke risk when compared to those with low VLDL levels. The absolute risk is not completely clear.

What this study shows is that the risk of stroke is not as simple as one thought. Certainly high blood pressure plays a role but the levels of triglycerides, VLDL and IDL lipoproteins also play a strong role in who gets thrombotic strokes and who does not. In the future, it may not be enough to just check a cholesterol and LDL level. The triglycerides need checking for certain and the IDL and VLDL levels need to be added to a basic lipid profile.