High Homocysteine Levels Linked to Alzheimer's

A new study has found that people with elevated levels of homocysteine in the blood have nearly twice the risk of developing Alzheimer's disease (AD) vs people with normal levels. The findings were reported in the February 14, 2002, issue of The New England Journal of Medicine.

The study was conducted by researchers at Boston University (MA, USA) and Tufts University (also in Boston), based on data on 1,092 dementia-free participants. The participants, whose average age was 76, were enrolled in 1976-78. Their plasma homocysteine levels were measured in 1979-1982 and in 1986-1990. Age, sex, vascular risk factors other than homocysteine, and plasma levels of folate and vitamins B6 and B12 were also considered, as was late-onset genetic risk factor APOE-epsilon4.

Exams from 1986-1990 through December 2000 revealed that 111 people had developed dementia, including 83 diagnosed with AD. Elevated homocysteine levels, defined as greater than 14 micro-mol/l, doubled the chance that a participant would develop AD, and each 5 micro-mol/l elevation increased the risk by 40%. The analysis showed that people with consistently high levels throughout the study period were at highest risk for dementia and AD. The analysis also linked elevated levels at least eight years prior to a later diagnosis of dementia and AD. The association was strong and independent of all other factors considered. No direct association was found in this study between the development of dementia and serum levels of folate and vitamins B6 and B12 in subjects.

"The good news is that we may have found a potential risk factor for AD that is modifiable,” said Neil Buckholtz, Ph.D., chief of the Dementias of Aging program at the US National Institute on Aging. "We don't know yet whether reducing homocysteine levels will reduce dementia risk, but this is something that can and will be tested in clinical trials.”




Related Links:
Boston University
Tufts University