How long you live has a lot to do with your environment and lifestyle, but exceptional longevity may have even more to do with your genes. For the first time, researchers have identified a genetic recipe that accurately predicts who may live to 100 and beyond.
Scientists led by Dr. Thomas Perls at the Boston University School of Medicine conducted a genetic analysis of more than 1,000 centenarians and their matched controls and found 150 genetic variants or snippets of DNA that differed between the two groups. These variants identified people who lived to a very old age (past 100) with 77% accuracy, researchers found.
Further analysis identified 19 distinct genetic profiles associated with extremely long life; 90% of participants who lived to 100 possessed at least one of the signature genetic clusters. Each profile appeared to confer a different propensity to develop common age-related chronic diseases, such as heart disease, dementia or hypertension.
"We realize this is a complex genetic puzzle," Perls told reporters during a telebriefing discussing his findings. "We're quite a ways away still in understanding what pathways governed by these genes are involved and how the integration of these genes not just with themselves but with environmental factors are all playing a role in this longevity puzzle."
As a geriatric researcher, Perls has studied many factors that contribute to longevity, and he is the first to acknowledge that living longer isn't likely to be simply a matter of genes. His previous work has shown, for example, that among most elderly people who live into their 70s and 80s, about 70% of their longevity can be ascribed to environmental factors such as not smoking; eating a healthy, low-fat, low-calorie diet; and remaining socially engaged and intellectually active throughout life.
Still, it seems clear that those who live to an exceptionally ripe old age are benefiting from a special DNA boost. In fact, Perls believes that the older a person gets, the more likely it is that his or her genes are contributing to those extended years. His current genetic findings support that theory: the 19 most common genetic profiles that distinguished the exceptionally long-lived appear to be correlated with lower incidence of certain diseases. For example, some profiles were associated with lower rates of hypertension and diabetes, while another was linked to a reduced risk of dementia.
But that doesn't mean supercentenarians avoid these diseases altogether. Although Perls, who oversees the largest database on centenarians in the U.S., began his research with the assumption that 100-year-olds survive longer by escaping the age-related diseases that defeat the rest of us, his recent work reveals an alternative hypothesis: centenarians are no more immune to these conditions than anyone else, but they seem to be more resilient in surviving them.
That functional reserve may be traced in part to the unique genetic makeup of the superold, but Perls believes it is also influenced by the way they live their lives. Although most of us can't expect to become centenarians, Perls is hoping that his work will lead to better ways perhaps through pharmaceutical interventions based on the genetic clues to longevity to help more of us live like them.