Rheumatoid arthritis can affect adults of any age. It most commonly starts between the ages of 40 and 60.
As previously mentioned, rheumatoid arthritis is an autoimmune condition, which means it's caused by the immune system attacking healthy body tissue. However, it’s not yet known what triggers this.
Normally, your immune system works to make antibodies that attack viruses and bacteria, helping to fight infection. Rheumatoid arthritis causes your body’s immune system to mistakenly send antibodies to the lining of joints, where they attack the tissue around the joint.
This causes the thin layer of cells (synovial membrane) that covers your joints to become inflamed and sore, releasing chemicals that damage the nearby:
- Tendons (connect bone to muscle)
- Cartilage (connect bone to other bones)
- Ligaments (connect bone to cartilage )