Alex di Suvero/The New York Times/Redux

One of the fastest-growing segments of the Canadian population is its oldest citizens, those 100 years of age or more. Between 2006 and 2011, the number of centenarians jumped by almost 26 per cent to 5,825, a number that is expected to double in the next 10 years, and soar to near 80,000 when a healthy generation of baby boomers hits the milestone in the mid-21st century. Today’s centenarians were alive when the Titanic sank and have lived to see robots exploring Mars like photo-snapping tourists. They saw the advent of penicillin, insulin, polio vaccines, pacemakers and publicly funded health care, to name but a few advances that have contributed to longevity. Medical science is only part of the equation; researchers are finding this hardy group holds many keys to the secret of longer, healthier lives for the rest of us.

The world’s largest study of extreme old-agers is the New England Centenarian Study, which has gathered data on more than 1,600 centenarians worldwide since its start in 1995 under founding director Dr. Tom Perls, a geriatrician at the Boston Medical Center. Its website is a treasure trove of studies documenting the unique characteristics and commonalities of those living to extreme old age. Among the myths the studies shatter is that genetics alone account for advanced old age and that centenarians are the lucky few who have escaped major illness.

Centenarians tend to fall into three groups. Just 15 per cent reach 100 years with no clinical evidence of disease. “We call them escapers,” Perls writes in an overview of the studies. Another 43 per cent are “delayers,” those who don’t acquire age-related diseases until at least 80 years. Another 42 per cent are “survivors,” whose earlier bouts with cancers, heart issues or other age-related diseases have not significantly curtailed their lifespans.

The studies show centenarians are a diverse lot, varying in education, socioeconomic status, ethnicity, religion and diet. (An exception to the religion rule are the much-studied Seventh-day Adventists of Loma Linda, Calif., who have an average life expectancy of 85 years, far longer than the typical American’s. In part, researchers believe it’s because their religion forbids smoking and drinking and encourages exercise, a vegetarian diet, a sense of community and a strict adherence to a day of rest and reflection.) The research does reveal characteristics of those likely to reach 100. Many are incorporated into the site’s popular Life Expectancy Calculator (livingto100.com). Among the predictors:

• Few centenarians are obese.

• A long history of smoking is rare.

• At least half of centenarians have immediate family that lived to very old age.

• Children of centenarians tend to follow a parent’s path to a longer life and, like them, tend to be extroverts who are able to handle stress with little evidence of neurosis.

• 85 per cent of centenarians are women.

The disparity between genders is explained in part because women have lower probabilities of dying at all ages than men, who have higher rates of death by accident and misadventure in their early years.

Canadian experts in geriatric care tend to concur with the study’s conclusions. Dr. Samir Sinha, director of geriatrics at Mount Sinai Hospital in Toronto, who was appointed by the Ontario government this May to help craft a seniors care strategy, says a social network, a sense of purpose and engagement, physical exercise and preventive health care are as vital as good genetics. All of those priorities are likely to have a place in Sinha’s report, due late this year. The “poster child” for Sinha’s seniors strategy is a 102-year-old Toronto resident known as Mr. W., a witty and engaged retired architect who lives in a book-filled Toronto apartment. Sinha helped spring him from a hospital bed almost two years ago with the help of his physician, Dr. Mark Nowaczynski, clinical director of House Calls, an interdisciplinary team for frail, house-bound seniors. Though Mr. W. has multiple health issues, he’s not been back to the hospital since. Two Rubik’s cubes sit on a windowsill, testament to his sharp mental faculties. He’s the very essence of the optimistic, socially engaged centenarian.

“It’s not that centenarians have had particularly healthy lifestyles, other than not smoking, but that they have positive outlooks, are generally optimistic and don’t sweat the small stuff,” says Nowaczynski. “To witness Mr. W. expertly flirt with a beautiful young woman in the most daringly gentlemanly way is not only watching an artist at work, but a reminder that age is only time, and his zest for life is timeless.”

When Sinha finishes his seniors report later this year, he’s promised to give one of the first public copies to Mr. W. Like his fellow centenarians, he is both a link to the past and a harbinger of our future.