Growing up, I was one of the few students in my high school who could boast a full set of grandparents as well as living great-grandparents. Not only were my elderly relatives still living, several were thriving well into their nineties—in contrast to most in their age peer group, they were living independent, quality lives. In the past decade, many studies have suggested that ample physical exercise, a healthy diet, and regular intellectual stimulation are important to a better quality life as we age. But while the majority of Americans can now expect to live approximately 78 years, individuals like my great-grandparents are providing scientists with a better understanding of exceptional longevity, both in terms of genetics and lifestyle. Their discoveries offer new insights into what it means to successfully age.
A strong genetic component
Common wisdom suggests that the older one gets, the sicker one gets; aging is often described as the body simply wearing out over time. But Thomas Perls, a geriatrician and associate professor of medicine at Boston University, says that idea doesn’t hold when it comes to centenarians—those who live past the hundred year mark. “We found fairly early in our studies that there was something different going on with centenarians,” he says. “The vast majority of them, about 90 percent, are still independently functioning at the age of 93. Somehow they are able to delay age-related diseases and seem to be better at managing or dealing with disease than other people.”
To better understand the genetic contribution of this exceptional longevity, Perls and colleagues compared the genomes of more than 1,000 centenarians to a control group. After publishing and then voluntarily retracting the initial results from Science in 2010, the group added an additional sample of super-centenarians with an average age of 107 years, re-analyzed the data, and then published the new results in PLoS One in January 2012. The group demonstrated that examining 281 single nucleotide polymorphisms (SNPs) on 130 genes could reliably predict whether a person was in the centenarian or control group. More interesting, many of genes in the model are those already linked to age-related diseases.
“About 30 of these genes were involved with Alzheimer’s disease, another 30 with cardiovascular disease and then a group associated with diabetes and one with cancer. These are all age-related diseases,” says Perls. “But we also saw SNPs in genes involved with premature aging syndromes, too. So you have one type of mutation on a gene that causes severe premature aging in teens and people in their early twenties. And then here you have another mutation one that same gene that is associated with increased longevity.”
Using these SNPS, Perls and colleagues could predict who was a centenarian with 73 percent reliability for those 102 years of age and older and an astounding 85 percent for people 105 and older. Perls says this shows just how important the genetic component is for these super-agers.
“Our results go along with the idea that the genetic component of survival to these older and older ages gets stronger and stronger,” he says. “Genetics play a critical role in survival in these most extreme ages.”
Lifestyle is important, too
While genes play an important role in those who live beyond 100 years of age, lifestyle is also important to exceptional longevity.
“Certainly genes constrain how well we function,” says Arthur Kramer, an aging expert at University of Illinois at Urbana-Champaign. “But so do our choices and our lifestyles.”
Howard Friedman, a researcher at the University of California in Riverside and co-author of the forthcoming book, The Longevity Project: Surprising Discoveries for Health and Long Life from the Landmark Eight-Decade Study (Plume, 2012), helmed a longitudinal longevity study which has identified factors such as strong family ties, healthy lifestyles, meaningful work, and religious observance as being important to a long life. They have also found a conscientious personality is also key.
“It’s not random who becomes ill as they age,” says Friedman. “Most eye-opening is our finding that the risk factors and protective shields do not occur in isolation but bunch together in patterns. Studying these constellations can help us understand which of these can help predict more achievement, better social relationships and other elements of thriving that lead to longer, healthier lives.”
He cites the example of men who score low on conscientious personality measures. Though these individuals are often very bright, they are more likely to have unhappy marriages, to not pursue higher education, to drink and smoke more, and to be less successful in their careers. Friedman says that studies that only look at marriage or education statistics may be inadvertently missing critical pieces to the longevity puzzle.
Putting it all together
Perls suggests that understanding the genomes of centenarians and super-centenarians, and how they manage to deflect age-related disease, may offer us new opportunities to prevent disease.
“These people are somehow protected from age-related disease. And if we can better understand those processes that are protecting them from those diseases, that may translate into new therapies down the road,” he says.
In the meantime, however, both he and Friedman say that making healthier lifestyle choices are important for a better quality life through one’s golden years even for those without super-centenarian genes. Yet, Friedman notes, the ones who worry the most about successful aging are probably those who are currently on the right track.
“Ironically, prudent, persistent achievers with stable families and social networks are usually the ones most concerned with what they should be doing to stay healthy,” says Friedman. “And they are already doing it!"