After accounting for other factors that affect stroke risk, the researchers found the stroke risk was more than four times higher in people with the highest homocysteine levels than in people with the lowest levels of the amino acid.
The study appears in the Feb. 21 online issue of Stroke.
Previous studies suggest that high homocysteine levels increase the risk of ishemic stroke and heart and blood vessel disease.
However, the reasons for that are unclear. There is some evidence that homocysteine may damage blood vessels and predispose people to forming fatty deposits and blood clots in their arteries.
Here's where you can learn more about coronary disease.