Why do Buddists live longer?

Answer 1

The Buddha lived for about 80 years. The exact dates of his birth and death are conjecture. This is a reasonable age but not exceptional especially for a man of quiet habits, regular exercize and a simple diet.

Answer 2

There is an increasing body of evidence that people that meditate regularly are happier and healthier generally than people that don't. It may be that Buddhists are less prone to illnesses like Dementia because of meditation.