from David's bio:

How I Became Known As Wolverine

I am an artist and animator by trade. I was quite a healthy person all of my life. I was never overweight (everyone complained I was too skinny), had no known allergies and was rarely sick, other than an occasional flu. Even those were rare and I usually got over them in a shorter period of time than most people. At the age of 48, I did develop a touch of colitis, for reasons unknown. My primary care physician said that I had become a bit anemic from blood loss and suggested that I go to the hospital to receive a transfusion. While in the hospital, I allowed a gastroenterologist to convince me to undergo a colonoscopy, both for the colitis and because I was at the age that medical professionals recommend people to begin cancer screening.