Salt Lake City citizens in happy marriages scored an average of 2.1 years younger on the test, the highest in the nation.
"Marriage was a strong benefit for all Salt Lake City denizens," Roizen said.
Roizen said he wasn't sure what factors may have contributed to Salt Lake City coming out on top, but speculated it may have been a result of a strong religious presence reinforcing a commitment to marriage.
"I had no idea people in Salt Lake City were that happy with marriage," Roizen said.
Roizen said he was surprised to see Los Angeles and San Francisco, both traditionally healthy cities, fall into the bottom 10 of the happy marriage list.
Miami finished last in the rankings, adding on average 1.3 years to apparently unhappy married couples.
Salt Lake City
Raleigh-Durham-Chapel Hill, N.C.
Kansas City, Mo.
Grand Rapids, Mich. and Minneapolis-St. Paul, Minn.
Las Vegas, Nev.
San Francisco, Calif.
New York, N.Y.
Tampa Bay-St. Petersburg Fla.
San Diego, Calif.
Los Angeles, Calif. and Miami