New Risk Factor For Dementia

Feb. 14 -- You can't change most factors, like genes, that determine your risk for Alzheimer's disease or dementia. But new data suggests you may be able to limit your risks by altering your diet or taking dietary supplements.

A study, appearing in the New England Journal of Medicine, finds an association between elevated levels of homocysteine, an amino acid also implicated in heart disease and stroke, and the development of dementia and Alzheimer's disease.

The good news, say experts, is that taking folic acid supplements can lower homocysteine levels, which may make those levels a modifiable risk factor.

Researchers from Boston University and Tufts University in Medford, Mass., used data gathered earlier in what was called the Framingham Study, which aimed to identify factors that contribute to the development of heart disease. In the current study, researchers looked at homocysteine levels taken from blood tests of 1,092 dementia-free subjects aged 65 and older at several stages.

Over the course of eight years, 111 subjects developed dementia, including 83 who developed Alzheimer's disease. When the subject's homocysteine levels were compared, the researchers found that higher levels were associated with increased dementia and Alzheimer's. Specifically, every 5 micromols per liter increase in homocysteine raised the risk of Alzheimer's disease by 40 percent. And a homocysteine level greater than 14 micromols per liter nearly doubled the risk of developing the disease.

Even after adjusting for factors that have been shown in previous studies to affect Alzheimer's disease risk, such as education and genetics, the association still held.

"This suggests that there was an effect of homocysteine on the development of dementia that was independent of the effect of [other] associated risk factors," says Dr. Philip Wolf, professor of neurology at Boston University School of Medicine and principal investigator of the current study and of the Framingham Study.