I think you will see an increase in older disc golfers after the sport has been around longer. The masters and grandmasters fields are way way bigger than they were just 15 years ago. I remember when our regional events typically had a masters field of 3-4 and now our B-tiers often have around 15-18 masters on average. Look at how many masters compete at the pro worlds compared to 15 yrs ago. (Incidently as of Jan 1 2007 I became elgible to compete in masters myself
DG is a non-impact sport that can be played for life provided you are in decent health. I have personally known the reigning legends world champ Paul Fein for about 20 years and he plays about ten times the amount of rounds I do and for a guy in his 70's he ain't bad (hence the world champion title).
Meds that are effective in treating and/or relieving arthritis:
Chondroitin (These first three are available in one tablet Triple-flex)
Omega 3 fatty acid ie. flax seed oil, fish oil, borage oil