In general, osteoarthritis happens as people get older. Younger people may get it from one of several different causes:
For people younger than age 45, osteoarthritis is more common among men. After age 45, osteoarthritis is more common among women. Osteoarthritis occurs more often among people who are overweight. It also occurs more frequently in those who have jobs or do sports that put repetitive stress on certain joints.
- Injury or trauma to a joint
- A genetic defect involving cartilage