In the autopsied brains of people who had experienced cognitive decline and dementia, 45 percent of the risk for dementia was associated with pathologic changes of Alzheimer's disease. Another ten percent of dementia risk was associated with Lewy bodies, neocortical structural changes that indicate a degenerative brain disease known as Lewy Body Dementia, believed by some clinicians to be a variant of Alzheimer's and/or Parkinson's disease. But a third of the risk for dementia (33 percent) was associated with damage to the brain from small vessel disease.
Dr. Thomas Montine from University of Washington and his colleagues believe that this small vessel damage is the cumulative effect of multiple small strokes caused by hypertension and diabetes, strokes so small that the person experiences no sensation or problems until the cumulative effect reaches a tipping point. This may be good news, says Montine. At a time when prevention and treatment for Alzheimer's remain investigational, methods for preventing complications of hypertension and diabetes are currently available.
These findings are very different from both conventional wisdom and from those of most autopsy studies of brain aging and dementia, says Montine. Why such different results? Perhaps because of the broad reach of the population on which the autopsy study was based, says Montine.
Most studies looking at the structural changes on autopsy in brains of persons with dementia have focused on participants in Alzheimer's disease center studies or in populations limited to one gender, ethnic or professional group. Individuals in this study were part of the Group Health Cooperative, one of the oldest and largest managed care programs in the United States, say the researchers.
MEDICA.de; Source: Federation of American Societies for Experimental Biology