Cholesterol-Stroke Relationship Puzzles Researchers

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An accompanying editorial by two stroke experts at Denis Diderot University in Paris offered one statistical explanation. It suggests that the combination of high cholesterol and elevated blood pressure might have killed off the most vulnerable part of the study population before their eighth decade -- leaving a hardier group of people behind.

Lewington said she wasn't prepared to join in on those speculations.

One expert said he isn't surprised by the findings, since stroke is a more complicated condition than heart attack.

Dr. Deepak Bhatt is associate director of the Cleveland Clinic's cardiovascular coordinating center. He noted that while heart attack has a single cause -- buildup of fatty deposits that block a coronary artery -- a stroke can be caused by a blockage in a carotid artery (a main blood vessel to the brain), a clot in an artery within the brain, a rupture of an artery, or an irregular heartbeat called atrial fibrillation that sends a clot to the brain.

There's also another scenario, in which someone survives a stroke but is so weakened that he or she quickly succumbs to heart disease, Bhatt said. In such cases, stroke is not even mentioned as the cause of the death, he said.

All this "can create something of a messy picture that can lead some people to conclude that control of cholesterol is not important for stroke prevention," he said. However, "from the patient's perspective, nothing here contradicts the fact that if they have high cholesterol, they should get it treated. It would be bad if the public gets a mixed message," Bhatt stressed.

More information

There's more on preventing stroke at the U.S. National Institute of Neurological Disorders and Stroke.