How old is the skinnest person in the world?

According to Ripley's Believe It or Not:

"Being too heavy or too skinny is very unhealthy for your body. Now on to the fact the skinniest person for his height and weight was "Slim The Shadow" of Baltimore (1930's) he was 7 Feet tall and weighed 90 Lbs. He kept the same weight for 16 years. The ideal medical weight for a man at his height would have been between 191-251lbs he was well under weight.'