If these symptoms are present in someone with osteoarthritis, they are caused by a condition unrelated to the osteoarthritis. Osteoarthritis affects almost 16 million men and women in the United States. The chance of developing osteoarthritis increases with age. Most people over age 60 have osteoarthritis to some degree, but its severity varies, and some people develop more severe symptoms than others. There are several factors that increase the risk for developing osteoarthritis, including heredity, obesity, injury or overuse of certain joints.
People born with joint abnormalities are more likely to develop osteoarthritis.
Some people have an inherited defect in one of the genes responsible for making collagen, a major component of cartilage. This causes defective cartilage, which leads to more rapid deterioration of joints. Obesity increases the risk for osteoarthritis of the knee. Maintaining ideal weight or losing excess weight may help prevent osteoarthritis of the knee, or decrease the rate of progression once osteoarthritis is established. Injuries contribute to the development of osteoarthritis.