Feb. 28, 2011 -- Having a mother with Alzheimer's disease may boost your risk of getting it more than having a father who suffers from the degenerative brain disorder, new research suggests.
"People with a mother with Alzheimer's disease had signs of brain shrinkage similar to people with early Alzheimer's," says researcher Robyn Honea, DPhil, an assistant professor of neurology at the University of Kansas School of Medicine.
Those with a maternal family history, she says, had twice as much gray matter shrinkage, which occurs with the disease, per year as those who had either a father with the disease or no parental history of it.
But a spokeswoman for the Alzheimer's Association who reviewed the findings takes exception to them, saying the sample size of 53 people is too small to come to any credible conclusions.
The study, supported by the National Institute on Aging and the National Institute of Neurological Disorders and Stroke, is published in the journal Neurology.
About 5.3 million Americans have Alzheimer's disease, according to estimates from the Alzheimer's Association.
Alzheimer's Disease & Maternal History: Study Details
Of those 53 people Honea evaluated, all were over age 60 and cognitively healthy at the start. There were 11 with a maternal family history, 10 with a paternal history, and 32 with no parental history of Alzheimer's.
Age is considered the most significant risk factor for developing Alzheimer's, Honea writes. Research has shown that first-degree relatives are at a fourfold to tenfold higher risk of getting the disease compared to those with no family history, and some other research has found a mother's history of the disease riskier for offspring than a father's history.
At the study start, all three groups were given a battery of tests to measure memory, language, and cognitive skills. They were given brain MRIs.
At 24 months, the tests and the scans were repeated and the researchers looked at brain shrinkage, which occurs with the disease.
Those with a mother with Alzheimer's disease had about 1.5 times more brain shrinkage per year than those with a father with the disease.
Those with a mother with Alzheimer's had twice the gray matter shrinkage as those who had no parental history or a father with the disease.
The performance on the cognitive tests did not change at two years.
''We were surprised that a group that seemed healthy could start to have shrinkage in these areas," Honea tells WebMD.
The new findings echo some of previous studies finding a maternal family history linked with higher risk than a paternal history, she says. "Our research is adding to this data signaling there is something specific inherited from the mother."
Honea controlled for such factors as age and gender and the link held. The link held, too, when she took into account the presence of the ApoE4 gene, which is linked to an increased risk for Alzheimer's disease.
While 63% of those with a maternal family history were ApoE4 carriers, 20% of those with a paternal history were and 15% of those lacking a family history were.