But that doesn't mean that Alzheimer's disease is definitely in your future, notes researcher Lisa Mosconi, PhD, assistant professor of psychiatry at NYU Langone Medical Center in New York.
Her advice: "If you're at risk of Alzheimer's because your mother had the disease, you need to make sure that you take special care of your health" to try to prevent or delay Alzheimer's disease.
Here's a look at Mosconi's findings -- presented in Chicago at the Alzheimer's Association International Conference on Alzheimer's Disease 2008 -- and reaction from experts.
Maternal History of Alzheimer's
Having a parent or sibling with Alzheimer's disease is a known risk factor for Alzheimer's. The new study is about figuring out how that happens.
Mosconi's team studied 66 healthy adults (average age: 64) with no signs of Alzheimer's, dementia, or milder mental problems.
Some participants' moms had had late-onset Alzheimer's disease, the most common form of Alzheimer's, which starts after age 65. Others had a father, but not a mother, with late-onset Alzheimer's. A third group had no parents with Alzheimer's.
Participants got positron emission tomography (PET) scans every year for two years to see how effectively their brain used sugar (glucose).
Throughout the study, all participants had normal mental skills. But those with a maternal history of Alzheimer's had a sharp decline in how well brain regions linked to memory and attention used glucose. Having a father with Alzheimer's didn't affect the PET scan findings.
It's too early to know if the drop in brain glucose metabolism will predict Alzheimer's. Mosconi's team will follow participants to check on that.
The researchers are also studying mitochondria, energy-making structures in cells, because mitochondria DNA are handed down maternally. Flawed mitochondria might be one piece of the Alzheimer's puzzle, but that isn't certain, Mosconi notes.
Clue to Alzheimer's?
The findings are "intriguing," Samuel E. Gandy, MD, PhD, and John R. Gilbert, PhD, tell WebMD.
Gandy, who chairs the medical and scientific advisory council of the Alzheimer's Association, points out that brain's glucose metabolism can fall decades before Alzheimer's starts.
"If you had a baseline [brain] scan and then a follow-up five years later and it showed that your glucose utilization was falling off rapidly and in a pattern consistent with Alzheimer's disease, that would be of concern," says Gandy. He also says "it's certainly plausible that if one inherits faulty mitochondria, that might put you at increased risk for Alzheimer's," though more work is needed to confirm that.
Gilbert -- a professor of human genetics who directs the Center for Genome Technology at the University of Miami Miller School of Medicine's Miami Institute for Human Genomics -- agrees.
"It may be that decreased glucose utilization doesn't necessarily mean you're going to get Alzheimer's disease but that, in conjunction with the wrong type of environment or some other genes that might give you a slight risk, would combine to give it to you," says Gilbert.
For some people, slowing glucose metabolism in the brain might be the tipping point. "But in a lot of people, it probably is just another insult... another hit in a biological boxing match," says Gilbert.
But family history or not, you can pack some punches of your own against Alzheimer's risk.
What You Can Do
What if your mother has, or had, late-onset Alzheimer's? Here's advice from Mosconi and Gandy:
- First, get a thorough medical checkup.
- Next, get any problems like blood pressure, high cholesterol, and diabetes under control.
- Upgrade your lifestyle with exercise and a healthy diet. If you smoke, quit. And find ways to exercise your brain by challenging your memory and attention.
"Those things are all good for you anyway, and until we have a pill that we can recommend for people, those are the sorts of recommendations that we're able to offer," says Gandy.
What About Dad?
Though Mosconi's findings are all about mothers, don't jump to the conclusion that dads don't affect Alzheimer's risk. "That's too far of a jump," says Mosconi. "There could be a paternal transmission factor but we don't really know what it is."
Gandy and Gilbert agree. Several Alzheimer's genes can come from either parent, notes Gilbert. And Gandy predicts that "there will be risk factors throughout the genome and some may be paternally transmitted... I think it would be too soon to exclude that."
By Miranda Hitti
Reviewed by Louise Chang
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