Scientists search for the genes behind healthy aging

Could healthy aging be in your genes? That's the question researchers from Scripps Translational Science Institute (STSI) are trying to answer with their long-term "Wellderly" study -- an analysis of the genome sequences of healthy elderly people in hopes of unlocking the genetic secrets behind lifelong health.

After eight years, the first findings have been released and reveal a higher-than-normal presence of genetic variants that may offer protective benefits against cognitive decline.

"The Wellderly, as we've defined, are exceptional individuals who live into their ninth decade and beyond without developing a significant chronic medical condition," STSI Director Eric Topol, M.D., who is one of the study's senior authors, said in a statement. "Our findings indicate that protection from cognitive decline is associated, not necessarily cause and effect, with health span."

Topol and his team enrolled more than 1,400 adults aged 80 to 105 who have not developed any chronic medical conditions or diseases, including cancer, stroke, Alzheimer's disease, Parkinson's disease, diabetes, and heart attack.

The researchers sequenced the whole genomes of just over 500 of these participants and compared their DNA to genetic data of another group of almost 700 individuals representing the general population.

In all, the researchers ended up analyzing more than 24 million individual gene variants in both groups.

The results showed that members in the Wellderly group had a significantly lower genetic risk for Alzheimer's disease and coronary artery disease. There was no difference between the two groups in genetic risk for cancer, stroke, or type 2 diabetes.

This suggests that protective behaviors or other genetic characteristics might be at play among the Wellderly. However, the study authors say it also demonstrates that protection from cognitive decline may be the key to good health as people age.

"We didn't find a silver bullet for healthy longevity," said study's co-author Ali Torkamani, Ph.D., director of genome informatics at STSI. "Instead, we found weaker signals among common as well as rare variant sites, which collectively suggest that protection against cognitive decline contributes to healthy aging."

This concept makes sense, Torkamani told CBS News, "as any gerontologist would say many of the healthy elderly people they meet are cognitively healthy and that's an important factor in healthy aging. But this is the first time as far as we know that we've seen a genetic component to this relationship."

These genetic variants may one day offer a pathway to develop new treatments for Alzheimer's disease, he said.

However, Dr. Scott Hebbring, an associate research scientist at Marshfield Clinic Research Foundation and a clinical adjunct Professor at the University of Wisconsin-Madison, points out that the study findings are limited.

"Although the results are interesting and raise new hypotheses, much of their results would not be considered 'statistically significant' under conservative standards as stated by the authors," he told CBS News. "Larger studies will be necessary to better understand the genetic component of healthy aging."

Still, experts say the study is a good foundation for future research in this field. "For many decades, we have searched for the genetic causes of disease in sick individuals," Eric Schadt, Ph.D., founding director of the Icahn Institute for Genomics and Multiscale Biology at Mount Sinai, who was not involved with the STSI research, said. "The Wellderly Study presents an attractive alternative by studying those who are well in order to uncover the solutions nature has provided to protect us against disease. The initial discoveries around protective factors for Alzheimer's disease and coronary artery disease demonstrate the keys the Wellderly may hold in unlocking ways in which we all may live healthier lives."

The researchers have made all their data available to the public to help spur further research.