Who Gets Alzheimer's? Genes Hold Key
But Genes Aren't Destiny, Study of Identical Twins Shows
When 1 Twin Has Alzheimer's continued...
If Alzheimer's disease was strictly genetic, one identical twin should get
the disease about the same time as the other. But when both identical twins had
Alzheimer's, there was as much as a 16-year difference in age of onset.
That, Gatz says, clearly shows that there must be a strong interplay between
a person's genes and a person's environment.
"For instance, if twins share a gene that is a more risk-promoting gene
with regard to how they process fats, then eating more fats would be more
dangerous for them," she says. "If one twin ate very few fats, her risk
would be much lower. We are sure that kind of thing is going on. That is why it
is hard to talk about genetic risks independently of environmental
How to Avoid Alzheimer's
William H. Thies, PhD, vice president for medical and scientific affairs at
the Alzheimer's Association, says researchers have a good idea about what some
of the environmental risks may be.
"We've long recognized that education has an impact on reducing the
likelihood of Alzheimer's disease," Thies tells WebMD. "The other more
lately evolving ideas fit mostly around heart disease risk factors. Alzheimer's
risk is linked to high blood pressure, high cholesterol, high blood sugar, a
high-fat diet, a sedentary lifestyle, and the lack of social
We can't pick our parents, so there's not much we can do about genetic
risks. But Thies points out that there are several things one can do to cut
your risk of Alzheimer's disease -- especially if the disease runs in your
- Stay mentally active.
- Be socially involved.
- Get physical exercise.
- Eat a brain-healthy diet.
Genes aren't destiny, Gatz says. If you think you or a loved one may be
getting Alzheimer's disease, it's time to act.
"The strong message to people is if there is any kind of concern about
dementia, it is important to get a good professional evaluation," she says.
"There can be reversible causes of cognitive change. Or doctors may be able
to offer either psychological or medical interventions that can slow processes
of cognitive change."