On the other hand, the researchers noted in their report, the finding is "consistent with the suggestion that many more people than previously suspected have the potential, at least genetically, to survive to an exceptional age."
Interestingly, one cluster that included 30 centenarians had almost no longevity-associated variants, the researchers found. It's possible that's just good luck or healthy behavior, Perls and colleagues said, but it may also be true that rare genetic variants -- not analyzed in the study -- can take the credit.
That idea is bolstered by family histories, they said. Data was available for 17 of the members of the cluster, of whom 59 percent had a strong family history of longevity.
A closer look at the genes of those volunteers, said Perls and colleagues, "may be particularly fruitful."
The study is "very exciting for the whole field of genetics and genomics and personalized health care," said Dr. Kathryn Teng of the Cleveland Clinic, who was not involved in the study but who is director of clinical integration of personalized health care at the hospital.
"It can potentially give us a lot of information -- now, but also in the future -- to target wellness, and risk for disease and also to develop potential medications or treatments," she told MedPage Today in an interview at which a public information officer was present.
But, Teng cautioned, the data from the study is not ready for application in the clinic.
"From a clinical practice standpoint, when I'm seeing patients, this is really not useful and helpful right now," she said. Instead, doctors will likely have to continue doing what they have been doing -- counseling their patients on how to lead healthy lives.