A US study has linked a gene that helps people live longer to increased mental ability and delayed onset of Alzheimer’s Disease.
The study is published in the current issue of Neurology and was conducted by researchers at the Albert Einstein College of Medicine of Yeshiva University in the Bronx, New York, and forms part of the Longevity Genes Project.
Dr Nir Barzilai, director of the Institute for Aging Research at the Albert Einstein College of Medicine, and his team looked at 158 people who were aged 95 and over and descended from Ashkenazi Jews who originally came from Eastern Europe. They asked this group, and another group of people of the same age who were not of Ashkenazi descent to complete cognitive tests of mental ability.
The scientists found that those who completed the test successfully (by correctly answering 25 of thirty questions) were two to three times more likely to possess the W variant of the CETP gene than those who did not.
In a later study the researchers examined a group of 124 people also of Ashkenazi descent, aged between 75 and 85. In this study they found that the ones who did not develop dementia on follow up were five times more likely to have the CETP W gene than those who did not.
The researchers chose to look at Ashkenazi people because they came from a small number of ancestors, making it easier to detect the differences in the genetic make up of the individuals due to the more uniform nature of their genetic patterns compared to the public at large.
This research comes on top of earlier studies, also by Dr. Barzilai and his team where they first showed that CETP W helps people live longer and also pass this gene onto their descendants. This study suggested that CETP W changes the size of good (HDL) and bad (LDL) cholesterol molecules in the blood – which helps people live longer because the smaller ones get stuck in the blood vessels more easily, leading to clots.
The centenarians in that study were three times more likely to have the CETP W variant and also had the larger HDL and LDL cholesterol molecules in their blood.
This latest study suggests that the cholesterol changing properties of CETP W may be protecting mental function by preventing the build up of cholesterol in the brain’s blood vessels, thus reducing strokes and heart attacks, or by some other means that is yet to be discovered.
“Without good brain function, living to age 100 is not an attractive proposition,” says Dr. Barzilai in a press release. “We’ve shown that the same gene variant that helps people live to exceptional ages has the added benefit of helping them think clearly for most of their long lives."
In the population at large, the chances of living to 100 is one in 10,000. The Ashkenazi population has a strong family history of longevity. Dr Barzilai pointed out that the odds of living much longer are much increased if you already have a centenarian in your family, and it is not necessarily lifestyle related. Many of the long living Ashkenazis are not vegetarian or athletic, and some of them have smoked for 90 years.
Cholesterol is an essential molecule for building cells. High levels of oxidized LDL cholesterol is thought to thicken artery walls (atherosclerosis) and increases risk of heart diseases. HDL cholesterol and the larger HDL in particular is thought to help remove cholesterol from thickened artery walls and high levels of HDL are linked to lower incidence of atherosclerosis and may even help to reverse the condition.
