80% of the population by age 65
Osteoarthritis is a very common condition. It is estimated that up to 80% of people aged 65 will have at least one joint affected by osteoarthritis. It is important to realize that osteoarthritis is only one of many types of arthritis. Other types include rheumatoid arthritis, psoriatic arthritis, gout or pseudo gout, ankylosing spondylitis, septic arthritis and a few other types.
In a lot of people, especially early on, it causes mostly an inconvenience, but it can lead to significant pain and profound limitation of mobility.