MONDAY, July 17 (HealthDay News) -- Who's at highest risk for developing Alzheimer's disease as they age?
Researchers say they're getting closer to answering that question, which, in turn, could help pave the way to interventions that could slow or stop the illness.
A new "Dementia Risk Score," for instance, appears able to predict risk 20 years down the line for people who are currently middle-aged, a new study finds.
That study and several others are being presented at this week's International Conference on Alzheimer's Disease and Related Disorders, held in Madrid from July 15-20. The conference is sponsored by the Alzheimer's Association.
Alzheimer's is largely a disease of aging and, as America's post-war Baby Boomers get older, the number of people with the condition is expected to soar. According to the Alzheimer's Association, about 4.5 million Americans currently have the disease, a number that's already doubled since 1980.
"Age is critically important," confirmed Dr. John C. Morris, a member of the board of directors of the Alzheimer's Association and director and principal investigator of the Alzheimer's Disease Research Center at Washington University in St. Louis. "As the Boomers get older, people are interested in looking at risk factors that may be operating in midlife which could be modified and prevented, such as diabetes, high blood pressure and high cholesterol."
"None of these factors have definitively been proven to be a cause of Alzheimer's," Morris continued, "but it doesn't hurt to get blood pressure under control."
To develop the new Dementia Risk Score, researchers in Sweden looked at data on over 1,400 people participating in a cardiovascular trial. All of the participants had been examined once at midlife and then again when they were about 70 years old.
Several factors predicted onset of dementia, the research team found, including older age, low education, high systolic blood pressure, high cholesterol, obesity and physical inactivity.
A higher score at midlife correlated with an increased risk of developing dementia later on. Only one percent of those who had a very low midlife risk score went on to develop dementia, while 16.4 percent of those in the highest risk score developed the condition.
The tool needs to be validated in another population and possibly further developed before being adopted by clinicians, said study lead author Tiia Ngandu, a researcher with the Aging Research Center at the Karolinska Institute in Stockholm.
But even at this early stage, Ngandu said, "I believe that the Risk Score can be used both as a means to inform both physicians and general public about the important risk factors in dementia. And also it could probably be used to detect which individuals are most at risk."
Once people at high risk are identified, physicians can try to influence risk factors such as obesity and high blood pressure in the hope of preventing dementia, Ngandu added.
A second study looked at data from the Massachusetts-based Framingham Heart Study to see if there was an association between higher stroke risk and more rapid brain changes as shown on MRI.
As it turned out, there was a significant tie-in between the score on the Framingham Stroke Risk Profile (a measure of 10-year risk for stroke) and rate of brain volume loss. The association was nearly twice as strong for men as for women.
Modifying stroke risk factors may also reduce the risk for dementia, the study authors concluded. Important stroke risk factors include smoking, high blood pressure, diabetes and heart disease.
"If vascular risk factors contribute to accelerated brain aging, then we should treat them," said study lead author Dr. Charles DeCarli, director of the Alzheimer's Disease Center at the University of California at Davis. "You might be surprised to find that many people are diagnosed with these diseases in middle or later life and choose not to follow the suggestions of their doctors to treat these problems. While the focus of treatment has traditionally been to avoid stroke and heart disease, we now suggest that treatment may avoid dementia as well."
Yet a third study looked at data on over 1,000 Japanese-American men who had had cholesterol levels tested five times between 1965 and 1993. They were also screened for dementia twice between 1991 and 1996.
In men who developed dementia, cholesterol levels declined at least 15 years prior to the diagnosis and remained lower. A decline in total cholesterol levels may correlate with the early stages of dementia, the authors concluded.
Finally, a fourth study found that people with poor lung function had an almost threefold greater risk of dementia than those who had good lung function. Treating lung problems, therefore, may also decrease the risk of dementia, said researchers at the VA Puget Sound Health Care System and the University of Washington, both in Seattle.