Lifespans of creatures on earth vary from a few hours to a couple of hundred years or more. A Vulcan is a non-human creature and so there's no reason why its lifespan should be similar to a human's.
Typically the colder a creature's blood the longer it can live, so maybe Vulcan's have colder blood than humans ...
Definitive answer unknown but a low blood pressure and high heart rate (80/40 and 242 bpm) contribute.
On reaching adulthood the aging process slows considerably.