March 9, 2010
L’Chaim! Want to live to 100? Check your genes.
Last week, Louis Biderman turned 99. Yet he can recall, in perfect detail, the trip he took to Los Angeles in 1938, 72 years ago. “I drove 3,000 miles to the coast, 3,000 miles back — all that within six weeks,” he said by phone from his Yonkers, N.Y., home. He was riding in a 1937 Pontiac, which he bought for $1,002.
Biderman may see nothing special about himself — “I’m not interested in glorifying my past,” he said — but his crystal-clear memories serve as a reminder that he belongs to a small demographic that is holding the medical community rapt: individuals who are living to 100 with no trace of illnesses that plague the elderly, including Alzheimer’s, dementia, diabetes and heart disease.
At the forefront of the research on these winners of the genetic lottery is Dr. Nir Barzilai, director of the Institute for Aging Research at Albert Einstein College of Medicine of Yeshiva University in New York.
For much of his career, Barzilai researched diabetes. Eventually, witnessing the ways in which the disease affects some people and not others led him to ask the inevitable questions about nature vs. environment and the hereditary aspects of age-related illness.
“In the discipline of medicine, [we] organize ourselves in groups,” he said in an interview. “We research cancer, heart disease, Alzheimer’s.”
But Barzilai recognized a common risk factor in many of those diseases — age.
“If we could slow aging,” he said, “we could impact all of those diseases.”
Wanting to take a closer look at centenarians, their lifestyles and their genes, Barzilai initiated a long-term study in 1998 that would allow researchers to find out what may set this group apart and lead to their excessive longevity. Through media promotion and word of mouth, he assembled a cohort of Ashkenazi Jews, as their genetic makeup is in many ways homogeneous. The group included not just people who had lived to 100 or close to it, but their 70- to- 80-year-old children as well.
“The offspring are very important because they inherited some of the [longevity] genes,” said Barzilai. Normally, this type of long-term study would include an age-matched control group for both the centenarians and their offspring, but because of the unique circumstances of the study, only the younger group had a match.
As Pinchas Cohen, professor and chief of endocrinology at UCLA’s Mattel Children’s Hospital and a colleague of Barzilai’s who also studies age-related disease, said, “With centenarians, the control group died 30 years ago.”
After the test subjects were recruited, researchers met with each family at the family’s home and tested participants’ memory and cognitive functioning, took a sample of their blood and performed an overall physical. Since then, the participants have been retested annually, and the project has been named the Longevity Genes Project and has added a sister project called the LonGenity Project.
Over the last decade, the group has been the foundation for Barzilai and his colleagues to test longevity theories. They’ve identified a handful of genotypes that come up repeatedly in the centenarians and may account for up to 80 percent of the reason for their unprecedented lifespan. But whether researchers will ever be able to pinpoint the cause in 100 percent of cases remains to be seen.
The chance of living to 100 is slim; most estimates place the likelihood at around one in 10,000. And for the general population, 80 percent of the propensity for longevity and good health comes from lifestyle and environment, while only 20 percent comes from genes.
It would seem, though, that the centenarians are the exception to that rule.
“Over 90 percent of centenarians smoked for prolonged period[s],” Barzilai said in an e-mail, “and almost 30 percent for more than 40 years. None of them was exercising regularly.”
Excluding the possibility that their longevity was linked in any relevant way to lifestyle, Barzilai and his colleagues focused their efforts on the group’s DNA.
The first goal was to test the group’s lipid profiles to search for a common thread. The lipid profile looks at overall cholesterol, including so-called good and bad cholesterol, and triglycerides, the fats that circulate throughout the blood. The lipid profile is an indicator of a person’s risk for developing cardiovascular disease, hypertension and metabolic syndrome.