Cecily O'Connor
RedwoodAge.com
By the time Alzheimer's disease has developed, it has usually damaged the brain beyond repair.
New research found that an individual's memory may actually decline before age 60. That means some boomers with a common genetic risk factor for Alzheimer's disease could begin to have memory declines in their mid-50s, which is far earlier than previously thought, according to a Mayo Clinic study in the New England Journal of Medicine.
Tests given to 815 people found that approximately one out of four people have one copy of the APOE e4 gene - the major genetic risk factor for developing Alzheimer's disease at older ages. About 2 percent have two copies of the gene. Each additional copy of this gene is associated with a higher risk of Alzheimer's disease.
"This study highlights the idea that Alzheimer's disease is a progressive disorder that likely begins well before clinical diagnosis," said Dr. Creighton Phelps, director of the Alzheimer's Disease Research Center program for the National Institute on Aging, which funded the Mayo study. "Additional research is needed to identify those at high genetic risk and develop methods to delay disease progression."
While there is no cure for Alzheimer's, new gene discoveries could facilitate development of therapeutic drugs. Future treatments may be most effective if started in middle-aged people before disabling memory and thinking problems, or extensive brain pathology develop.
Other studies have shown that diet may play a role in staving off the disease, that socializing - particularly with caregivers - slows its progression and that exercise had a big impact on age-related mental decline. "Neural workouts" are also suggested as a way to stay mentally healthy.
To be sure, the dementia associated with Alzheimer's is only one type of mental decline associated with aging, but it is the most prevalent.Overall, Alzheimer's is expected to affect about 15 million Americans by 2050, up from 5 million today.
One in eight baby boomers are expected to contract this fatal disease, which gradually eats away at a person's memory and ability to learn, reason, communicate and, eventually, carry out daily physical activities.
Do You Carry the Gene?
"Having a parent or sibling with
Alzheimer’s disease does increase one’s risk somewhat above the general
population’s risk of developing the disease, but such a family history should
not cause undue anxiety," according to an Alzheimer's
Association article on genetic testing. That's why some people
with such family histories may opt to have a genetic test if they want more
information about their vulnerability to the disease.
However, "genetic testing for APOE-e4 is controversial and should only be undertaken after discussing the benefits and risks with a physician or genetic counselor," the association added. Health professionals do not currently recommend routine genetic testing for Alzheimer’s disease. Although, testing for APOE-e4 is sometimes included as a part of research studies.
There is no way to change one’s APOE-e4 status - and not all those with the gene develop Alzheimer's - but lifestyle changes may help reduce the potential effects of having APOE-e4. This includes a healthy diet, exercising and staying mentally active.
Pre-clinical Alzheimer's
"While other age-sensitive cognitive skills also change, memory,
specifically, appears to decline more quickly in APOE e4 gene carriers, and it
is this pattern of cognitive aging that is similar to (but much milder than)
what we expect to see in patients with Alzheimer's disease," said Dr.
Richard J. Caselli, chair of Mayo Clinic's Neurology Department in Arizona and
lead author of the research study. "This suggests that seemingly normal
age-related memory loss may actually represent very early, preclinical-stage
Alzheimer's disease."
Using brain-imaging techniques to study some of the same individuals in a previous study, Mayo Clinic researchers reported brain changes in people at three levels of genetic risk, some of which surface decades before the onset of symptoms.
These findings reinforce the importance of conducting prevention trials starting in late middle-age, researchers said. They also suggested that brain-imaging techniques could be used to evaluate potential treatments without having to study thousands of people, or wait years to see which people develop symptoms.
