Alzheimer's disease among twins varies by individual
Is it typical for twins to both get Alzheimer's disease and experience the same symptoms at the same times? – Angie's List member Jim Palmer of Sasser, Ga.
Certainly, it's more likely if one twin has the disease the other could too, says Brenda Plassman, an associate research professor with highly rated Duke University Medical Center in Durham, N.C. But it's not necessarily typical.
In identical twins where one has Alzheimer's, the second twin develops the disease about one-third of the time, says Plassman. In fraternal twins, the rate is half that – similar to non-twin siblings. "This means that if one twin gets Alzheimer's disease that it's not inevitable that the other twin will," she says.
In addition, the age of onset and symptoms vary considerably from one twin to the next, and environment seems to play a role. "We found that within twin pairs, that the twin with greater job 'cognitive' demands such as reasoning, mathematics, language and vocational training had lower risk of Alzheimer's disease," Plassman says.
Still, the efficacy of many suggested approaches, such as mental stimulation, exercise and dietary changes, to prevent or slow Alzheimer's progression is unclear, according to the National Institutes of Health. But as twin studies demonstrate, more than simple genetics is at play in determining who does and doesn't get Alzheimer's.
"There's quite a bit of variability between individuals," Plassman says.
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