Arthritis, the leading cause of disability in the U.S., actually comprisesmore than 100 diseases that involve the joints, the tissues that surround the joints, and other connective tissue. Arthritis affects approximately 43 million Americans, including 300,000 children. The Arthritis Foundation estimates that arthritis costs society about $125 billion annually, $43 billion in direct medical costs and $82 billion in indirect costs.
The most common form of arthritis is osteoarthritis, or degenerative arthritis, which affects approximately 10% of Americans, rising to 70% to 90% of people older than 75. Other types of arthritis include rheumatoid arthritis, juvenile rheumatoid arthritis, lupus, gout, and fibromyalgia.
Risk factors for arthritis include female gender, older age, obesity, physical inactivity, sports and other injuries to a joint, and occupational lifting.