Health Topics A-to-Z
What Is It? Arthritis involves inflammation of the joints that causes pain and swelling. Although many people believe arthritis is a disease of old age, various forms of arthritis can affect just about anyone at any age. When arthritis occurs in children younger than age 16, it is called juvenile arthritis. A CDC survey in 2007 estimated that 294,000 children in the United States have some form of the disease.