Rheumatoid arthritis (RA) is a chronic disease that causes pain, stiffness, and swelling primarily in the joints. RA affects approximately 1.3 million Americans, but unlike the more common osteoarthritis (OA), RA is not associated with factors such as aging, obesity or injury. Learn more about the difference between RA and OA

RA occurs when the body’s immune system malfunctions, attacking healthy tissue in addition to its normal enemies, foreign invaders such as bacteria and viruses. This malfunction causes inflammation which leads to pain, swelling in the joints and may eventually cause permanent joint damage and painful disability.

What causes RA?

Although the exact cause of rheumatoid arthritis is unknown, experts believe that the disease may be the result of a combination of factors, including:

• Genetics – Certain inherited genes may make you more likely to develop RA.
• Environment – RA may be triggered by an infectious agent such as a bacteria or virus in an individual genetically predisposed.
• Other – It is also thought that other factors such as female hormone and the body's response to stressful events may also play a role.

Who's at risk for RA?

• Onset usually occurs in people between the ages of 30 and 50 years old, though RA can occur at virtually any age.
• Approximately 70% of people with RA are women.
• RA often goes into remission in pregnancy but symptoms tend to increase after the child is born and RA also develops more often in the year after giving birth.