Below is an instruction from Human. Write a response.
    ### Instruction:
    What causes Osteoarthritis ?
    ### Response:
    Risk Increases With Age Researchers suspect that osteoarthritis is caused by a combination of factors in the body and the environment. The chance of developing osteoarthritis increases with age. It is estimated that 33.6% (12.4 million) of individuals age 65 and older are affected by the disease.
    