Rheumatoid arthritis affects more than 400,000 people in the UK and often starts when a person is between 40 and 50 years old.
The NHS explains: “In rheumatoid arthritis, the body’s immune system targets affected joints, which leads to pain and swelling.
“The outer covering (synovium) of the joint is the first place affected.
“This can then spread across the joint, leading to further swelling and a change in the joint’s shape. This may cause the bone and cartilage to break down.