People with Alzheimer’s disease often have problems with blood vessels in the brain that may be making symptoms worse, a new study reports. The findings may help to explain why measures that can improve blood vessel health in midlife — like eating a heart-healthy diet, getting regular exercise and keeping cholesterol levels in check —may help to curb Alzheimer’s in old age.
While strokes and blood vessel disease are commonly recognized causes of dementia other than Alzheimer’s, the study provides additional evidence that blood vessel disease likely plays an important role in many cases of Alzheimer’s as well. People who have signs of both Alzheimer’s and blood vessel or vascular disease are sometimes referred to as having “mixed” dementia.
The findings, published in the journal Brain, come from researchers at the Perelman School of Medicine at the University of Pennsylvania who looked at vascular health across a wide range of brain ailments. They found that limited blood flow to the brain played a role in many brain disorders, including Parkinson’s disease and Lou Gehrig’s disease (also known as ALS). But compared to these conditions, vascular disease was far more common among people with Alzheimer’s
"While there was evidence already to suggest that vascular disease could play a role in neurodegenerative disease, this is the first study to compare the burden of vascular disease across neurodegenerative diseases with multiple, distinct or different origins," said senior author Dr. John Q. Trojanowski, director of the Alzheimer's Disease Core Center at the University of Pennsylvania. "We were surprised to find such a strong link to vascular disease in Alzheimer's disease, especially in younger patients, in comparison to individuals with other neurodegenerative diseases."
For the study, the researchers analyzed 5,715 cases from the ongoing National Alzheimer's Coordinating Center database, which has been collecting data about Alzheimer’s cases across the country. Almost 80 percent of the Alzheimer's disease patients showed some degree of blood vessel problems. Problems ranged from hardening of the arteries, blocked or narrowed blood vessels, to+ bleeding in the brain.
"In the absence of any disease modifying therapies to change the course of Alzheimer's, we hope that the diligent use of existing treatments for vascular conditions and the implementation of campaigns promoting healthy lifestyles in young and middle aged people may have a positive impact on preventing or reducing dementia symptoms in Alzheimer's and Parkinson's disease " said Dr. Jon B. Toledo, a study author.
The authors note that many drugs being aimed at Alzheimer’s are targeted at beta-amyloid, the toxic protein that builds up in the brains of patients with the disease. But it may be important to take into account problems related to poor blood flow as well, they say, and to include such patients in future studies of Alzheimer’s treatments.
Source: JB Toledo, SE Arnold, K Raible, et al: “Contribution of Cerebrovascular Disease in Autopsy Confirmed Neurodegenerative Disease Cases in the National Alzheimer’s Coordinating Centre.” Brain, epub ahead of print, July 10, 2013.