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News tips from the June issue of Stroke: Journal of the American Heart Association

American Heart Association

Changes in retina linked to poorer cognitive function, dementia

DALLAS, June 7 - Abnormalities in tiny branches of retinal blood vessels might serve as an early warning system for dementias associated with Alzheimer's disease, stroke, and other diseases, researchers report in the June issue of Stroke: Journal of the American Heart Association.

In the study of more than 8,000 middle-aged people who had not suffered a stroke, those with impaired mental function were about three times more likely to have abnormalities in the retinal vessels, called arterioles.

"There has been a hypothesis for some time that some vascular cause other than the aging process itself was associated with Alzheimer's and stroke," says Tien Yin Wong, M.D., M.P.H. "This study shows that people with cognitive dementia are more likely to have pathological changes in the retinal vessels, which may be a reflection of similar pathological changes in the brain."

Retinal examination could potentially provide an inexpensive, noninvasive way to diagnose and evaluate vascular dementia in the general population, says Wong, a researcher and professor of ophthalmology at the Singapore National Eye Center and National University of Singapore.

Previous research by this group found that retinal abnormalities predict stroke independently of traditional risk factors. The study was funded in part by the National Heart, Lung, and Blood Institute.

Low vitamin C intake linked with stroke risk

DALLAS, June 7 - Low vitamin C concentration in the blood stream may be a risk factor for stroke, especially among hypertensive and overweight men, Finnish researchers report in the June issue of Stroke: Journal of the American Heart Association.

Men with blood vitamin C levels in the lowest quarter [less than 28.4 micromoles per liter (umol/L)] had a 2.1 times higher risk of any type of stroke compared with men in the highest quarter (more than 64.96 umol/L). The likelihood was higher for men who also had hypertension or were overweight.

There is a moderate correlation between vitamin C intake and the amount of vitamin C circulating in the blood, says lead researcher Sudhir Kurl, M.D. The lowest quartile in this study had an intake roughly equivalent to the vitamin C in half a glass of orange juice a day.

A possible effect of vitamin C is that it enhances endothelial function, which inhibits artery clogging and lowers blood pressure. However, the link could simply be that people who take vitamin supplements or eat vitamin-rich fruits and vegetables may be more health-conscious than those who don't. So vitamin C alone may not be responsible for the results of the study, he says.

The research was compiled from a prospective follow-up study of 2,419 Finnish men between the ages of 42 and 60 and was funded in part by the National Heart, Lung and Blood Institute.

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