If you live in the Triangle, you have discovered the fountain of youth.

A study of the 50 largest metro areas in the U.S. finds the Raleigh-Durham-Chapel Hill area is among the 10 “youngest” places in the country. The study, released today, looked at 52 factors and ranked the Triangle No. 8 nationally, just below No. 7 San Diego and just above No. 9 Minneapolis-St. Paul, in terms of how old we really are.

According to the U.S. Census Bureau, our average annual age is 46.8. According to the study by RealAge.com, we’re more like 45.9.

The study was culled from questionnaires RealAge collects at its Web site. A thousand surveys for each of the 50 areas was randomly selected from questionnaires submitted over the past three years, according to RealAge’s chief medical officer, Dr. Keith Roach. RealAge says 27 million people have filled out the questionnaire since its introduction in 1999. The questionnaire is one of several tools offered by health Web site.

The Triangle’s ranking comes as a bit of a surprise, especially considering the five key health factors that accounted for 50 percent of a city’s “real age”: cholesterol, smoking, blood pressure, diabetes and weight. Located in a state that tips the scales when it comes to obesity (North Carolina ranked 10th in the nation in adult obesity according to a study last year) and is in the heart of tobacco country, Triangle residents nevertheless manage to live younger than their years.

Curiously, again considering the state’s obesity standing, the Triangle ranked as the nation’s youngest area in terms of cholesterol levels.

“Honestly, I was surprised at that,” Roach said Monday from New York. “But the ranking took into account good and bad cholesterol, and cholesterol can be affected by good genes and whether people are taking their medications for it.”

The Triangle also got good grades for drinking responsibly — at least among its men, who ranked sixth nationally. The Triangle’s women did not crack their gender’s top 10 list.

A curiosity on the subject of alcohol: Salt Lake City, which ranked as the nation’s youngest city overall, didn’t break the top 10 in responsible alcohol use.

“An average of one glass a day for men and a half a glass for women can lower your mortality rate,” Roach explained. It’s when you get to two drinks a day or more that alcohol negatively affects your lifespan. And four drinks or more at one time? “That’s considered binge drinking and your risk of accidental death goes sky high,” said Roach. Roach said Salt Lake City’s poor showing was based on the fact that people either drink too little or way too much.

We also sleep well in the Triangle In fact, only people who sleep better are in Austin and New York, the city that allegedly doesn’t sleep.

On smoking, another one of the study’s Big Five, the Triangle ranked 16th. “It was one of the few cities in the Southeast with a good score,” said Roach.

One area the Triangle needs to keep an eye on: hypertension. The Triangle ranked 31st nationally, prompting Roach to suggest our public health officials might want to step up free blood pressure tests.

Elsewhere in North Carolina, the Charlotte area ranked 34th, with residents there a tenth of a year younger than their calendar age, while the Triad — Greensboro, Winston-Salem, Highpoint — ranked as the nation’s second “oldest” area, with residents there exhibiting bodies a half year older than their calendar age.

Roach said he filtered through 300 medical journals and sources ranging from Harvard Medical School to the U.S. Census Bureau to determine criteria for the study. Some insight into four of the categories used.

• Aspirin use. We consume a ton of aspirin every year in this country — 16 tons, actually, according to Roach. It’s regular consumption by men over 45 and women over 55 is generally beneficial, he said. Regular consumption by younger users “can do more harm than good,” resulting in points off.
• Marital status. “This one’s complex,” said Roach. “Happily married is the best. Unhappily married is worse than divorced. Living alone is bad, especially for men.” Simply having more social interaction reduces the four forms of risk considered in the survey: cardiovascular (heart and stroke), cancers, accidents “and all others, including diabetes, infectious diseases and my favorite, getting hit by a meteor.”
• Income. This category gave the highest rankings to the cities where it’s costliest to live: 1. San Francisco bay area, 2. Washington-Baltimore, 3. New York. Roach conceded that the incomes there are obviously higher because of the cost of living, and that disposable income would have been a better tool, but they weren’t able to gather that information.
• Employment: Another complicated area, said Roach. “Fully employed or being a student is good, being unemployed is bad. Having two jobs is bad, and being part time when want to be full time is almost as bad as unemployed.”

For more information on the study, visit RealAge.com.

Photo: Jack Benny was forever 39. Can Trianglites stay forever 45.9?