Dr. Tom Perls, the director of the New England Centenarian Study at Boston University Medical Center, estimates there are approximately 200-300 of these "supercentenarians" in the world.
"People who live to that age are incredibly heterogeneous, as if they have some key genetic features in common that get them to an incredibly old age," Perls told ABC News.
One commonality Perls' studies have found - Approximately 90 percent of superagers are women.
He speculates that having two X chromosomes offers a certain amount of protection from disease and disability.
"If one chromosome has some less-than-desirable aging or disease genetic variance, women seem to have the ability to choose a variant on the other chromosome that is more conducive to survival," he said.
One of Perls' studies also showed that women who conceived naturally and carried a baby to full term after age 40 are at least four times more likely than average to live to the age of 100.
As for living a clean lifestyle, Perls said the research is mixed, with one study showing approximately 20 percent of those over the age of 103 practicing truly horrendous lifelong health habits including smoking, drinking, eating junk food and avoiding exercise.
Perls recalled that the oldest woman on record, Frenchwoman Madame Jeanne Calment, who died in 1997 at the age of 122, smoked heavily until she was 100 years old and continued to smoke one cigarette a day thereafter. Perls wondered if she would have lived even longer had she kicked the habit.
However, Perls stressed that it is very rare to find a smoker who makes it past the century mark. The same holds truly of anyone who is even mildly overweight.