Emily Tremonti sits in front of her cake on her...

Emily Tremonti sits in front of her cake on her 110th birthday in Fairfield, Conn., on Dec. 6, 2014, in a photo provided by Mary-Kate Mele. Tremonti grew up with four sisters in Mount Vernon, N.Y. One also lived to 100. Credit: AP

Flipping the calendar to 2015 makes time seem fleeting, but some of us will have more years on this planet than we expect. Demographers tell us that centenarians -- people aged 100 and older -- are the fastest-growing segment of the U.S. population.

The number of centenarians increased by about 6 percent, to more than 53,000, between the 2000 and 2010 Census. Health officials predict that by 2050, roughly 800,000 Americans will hit triple digits.

This has sent dozens of researchers scurrying for their microscopes. The Institute for Aging Research, at the Albert Einstein College of Medicine in the Bronx, has identified longevity genes. Director Nir Barzilai said in September that his institute is trying to make drugs that will act like the genes and lengthen life.

But there's hope for the genetically ungifted, too.

Often, we believe that we will succumb to the same illness that killed our parents. However, about 40 percent of centenarians have survived a life-threatening illness -- such as cancer, heart disease or stroke -- according to the Long Life Family Study sponsored by the National Institutes of Health. These survivors needed less serious medical care during their illness and somehow just moved past it. This is a trait scientists have observed but haven't quite explained.

Mario Martinez says denial may help. He's a clinical neuropsychologist from the Biocognitive Science Institute who studies healthy centenarians in different countries. One characteristic that holds true across cultures is centenarians' refusal to accept statements such as "What do you expect at your age?" or "You're too old for that," Martinez writes in his 2014 book "The MindBody Code." He advises people who want to live long to dismiss stereotypes about reaching a particular birthday. Healthy centenarians view themselves as significantly younger than they are, remain curious and continue to plan for the future.

So it's as simple as "think young"? Not quite. Martinez also credits moderation. Some healthy centenarians are plump, but none that he met were obese. Some smoke cigars or drink alcohol, but they're not addicted. Many are religious, but aren't religious fanatics.

I'm glad that moderate habits, rather than abstinence, won the day. Another study seemed designed to champion abstinence, by following 73,000 Seventh-day Adventists, a Christian denomination that encourages members to be vegetarians and to abstain from alcohol, tobacco and caffeine. After six years, researchers from Loma Linda University found that the risk of death was lowest not among the most hard-core vegans, but for the more moderate pesco-vegetarians, who eat fish, dairy and eggs -- everything but meat and poultry.

As you plan your 2015, keep this in mind. It's one thing to live long, but even better to live well.

Anne Michaud is the interactive editor for Newsday Opinion.

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