Does climbing lead to pre-mature arthritis or is it more preventive? It is not conclusive yet, but most articles suggest that it may not increase the risk or show the same pattern of Osteoarthritis.
I just a came across an article, 'Sport climbing from a medical point of view: The finger joints of “elderly” climbers and adolescents' by Andreas Schweizer, Swiss Med Wkly. 2012 and it is an interesting article which overviews of the most common and most specific climbing related injuries.
"Most of the climbers concerned had performed bouldering at a high level and were older than 35 years. These climbers reported rare episodes of slight pain and stiffness on the dorsal side of the joints when hitting hard objects or after climbing intensively with the crimp-grip-position. . . The pain usually disappears after 3–5 weeks . . . The oldest climbers performing the sport at such a high level are generally not older than early fifties. However, it seems that the changes observed have arisen through adaptation and do not show the same pattern of the common inherited degenerative arthritis (poly-arthrosis). " See article: http://www.smw.ch/content/smw-2012-13688/