Scientists at Albert Einstein College of Medicine of Yeshiva University have found a "longevity gene" that may help diminish age-related cognitive decline in elderly.
With the new finding, they have stepped up efforts to develop drugs that mimic the gene's effect and help protect against Alzheimer's disease.
"Most work on the genetics of Alzheimer's disease has focused on factors that increase the danger," said Dr Richard B. Lipton, the Lotti and Bernard Benson Faculty Scholar in Alzheimer's Disease and professor and vice chair in the Saul R. Korey Department of Neurology at Einstein and senior author of the paper.
In a 2003 study, Lipton and his colleagues identified the cholesteryl ester transfer protein (CETP) gene variant as a "longevity gene" in a population of Ashkenazi Jews.
The favourable CETP gene variant increases blood levels of high-density lipoprotein (HDL) - the so-called good cholesterol - and also results in larger-than-average HDL and low-density lipoprotein (LDL) particles.
In the new study, researchers hypothised CETP longevity gene might also be associated with less cognitive decline, as people grow older.
They examined data from 523 participants from the Einstein Aging Study.
"We found that people with two copies of the longevity variant of CETP had slower memory decline and a lower risk for developing dementia and Alzheimer's disease," said Dr Amy E. Sanders, assistant professor in the Saul R. Korey Department of Neurology at Einstein and lead author of the paper.
"More specifically, those participants who carried two copies of the favorable CETP variant had a 70 percent reduction in their risk for developing Alzheimer's disease compared with participants who carried no copies of this gene variant," Sanders added.
The favourable gene variant alters CETP so that the protein functions less well than usual.
Lipton said drugs are now being developed that duplicate this effect on the CETP protein.
"These agents should be tested for their ability to promote successful aging and prevent Alzheimer's disease," he added.
The findings are published in Journal of the American Medical Association.