The study, by Anne B. Newman, M.D., M.P.D., a geriatrician at the University of Pittsburgh School of Medicine and an associate professor of medicine and epidemiology, investigated the associations between the risk of dementia, Alzheimer's disease and vascular dementia in people with a history of clinical cardiovascular disease (heart attack, angina or peripheral vascular disease) or markers for cardiovascular disease (including ECG abnormalities, left ventricular hypertrophy, carotid artery thickness or carotid stenosis).
"We found that those with cardiovascular disease had an increased risk of dementia of about 30 percent, only partially explained by stroke," Dr. Newman said. "Although the relative risk was moderate, the high prevalence of cardiovascular disease coupled with the high risk of dementia in older adults would suggest that prevention of cardiovascular disease may be the most effective preventive measure we have for the prevention of dementia."
The study is part of the Cardiovascular Health Study, which included 5,201 people aged 65 and older in 1989/90 and an additional 687 African-Americans enrolled in 1992/93 from four U.S. communities. Ten annual clinical exams took place from study entry until 1999. These exams included cognitive testing and other physical, psychosocial and laboratory measures. Of that group, 3,602 participants who had undergone an MRI in 1992/93 were selected for further cognitive assessment, which was concluded in 1999.
The study found that of the 3,602 participants in the Cognition Study Group, 480 had some type of dementia. Of these, 330 had Alzheimer's disease (69 percent), 52 had vascular dementia (11 percent), 76 had mixed vascular and Alzheimer's disease (16 percent) and six had Parkinson's disease (1 percent). Vascular dementia is the result of insufficient blood flow to the brain.
"The risk of dementia was highest in those participants with peripheral arterial disease," Dr. Newman reported. "The risk of Alzheimer's disease was also higher in those with cardiovascular disease, though this was partly explained by other dementia risk factors."
The study is supported by grants from the National Institutes of Health - HL 85079 - 86 and R01-AG-15928.