High Blood Triglycerides Linked to Stroke Risk
THURSDAY Dec. 27, 2007 -- High blood levels of the fats called triglycerides are associated with an increased risk of stroke, a new study finds.
"There's a lot of evidence emerging that they have a strong effect on vascular [blood vessel] risk as a whole," said study senior author Dr. Bruce Ovbiagele, associate professor of neurology at the University of California, Los Angeles.
The study of more than 1,000 people treated for ischemic stroke -- the kind that happens when a clot blocks a blood vessel of the brain -- found that those with the highest levels of triglycerides were more than twice as likely to suffer such a stroke.
The findings are published in the Dec. 26 issue of Neurology.
Like cardiologists, neurologists concerned with the bad effects of blood fats have concentrated mostly on LDL cholesterol, the "bad" kind that forms artery-blocking clots, Ovbiagele said. The benefits of lowering LDL cholesterol levels, in terms of heart disease and stroke, are well known, he said.
"Our study would seem to indicate that triglycerides are more important than LDL cholesterol," he said. "But they haven't been studied in the way of reducing their levels and seeing if that reduces stroke risk. If we reduced triglycerides as aggressively as we reduce LDL cholesterol, we might have equally lower risk, but nobody knows."
The role of LDL cholesterol and other blood fats in stroke has drawn increasing attention from a new breed of specialist, the vascular neurologist, said Dr. Cathy Sila, head of vascular neurology at the Cleveland Clinic.
The study of blood vessels in stroke is much more complex than in heart disease because of the great variety of vessels to be dealt with and the different kinds of stroke that can occur, Sila said.
"Almost all heart attacks are due to atherosclerosis," she said, referring to artery blockage. "Only about half of ischemic strokes are related to atherosclerosis. And we have vessels as big as the carotid artery, which is the size of a pencil; intracranial arteries, the size of linguini; and vessels in the brain as big as the size of a human hair."
The connecting factor in assessing the risk of ischemic stroke in many cases is not just blood levels of fat but the metabolic syndrome, a constellation that includes high blood fat levels, high blood pressure levels and obesity, Sila said.
Success in lowering cholesterol levels with statin drugs has meant "a lack of attention paid to other lipid fractions," she said.
The reported association between triglyceride levels and stroke reinforces the standing recommendations for reducing known risk factors for vascular disease, both Sila and Ovbiagele said.
"We should focus on reducing LDL cholesterol as a primary goal but not ignore triglycerides," Ovbiagele said. "We should also consider a trial to lower triglycerides to see if we can improve on the benefits we get from lowering LDL cholesterol."
There's more on stroke risk factors at the American Heart Association.
Posted: December 2007