Axtually, queeq, that was more of a direct referecnce to Raz's question, showing him why Sauron didn't get the Ring while Gollum had it- because he didn't know. Not until Gollum was caught in Mordor.
As for your point, it is simply stated, many times in the books, that Gollum lives long because of his exposure to the Ring. That's all there is to it.