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What Causes Rheumatoid Arthritis?

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Unlike osteoarthritis, a condition caused by wear and tear on joints, rheumatoid arthritis happens when your immune system targets your joint linings. It’s a long-term condition that also affects other tissue, but the joints are usually the most severely affected.

Doctors don’t know exactly what causes RA. It may be a combination of genes and other things. Some researchers think an infection with a bacteria or virus can trigger the disease in some people, but so far, they don’t know what virus or other organism does that.

As rheumatoid arthritis develops, some of the body's immune cells start to attack healthy tissue, mistaking it for an invader. This triggers a chain reaction that leads to more inflammation and damage.

The main target of RA's inflammation is the synovium, the thin layer of tissue that lines the joints. The inflammation also spreads to other areas in the body, which can cause ongoing pain, fatigue, and other problems.

What Makes Me More Likely to Get Rheumatoid Arthritis?

The disease is more common in women than in men. It’s more likely in women who've never been pregnant and in those who've recently given birth.

The condition can also run in families.

RA becomes more likely with age, too, but it’s not a normal part of aging. Cigarette smoking may also raise your chances of getting it.

WebMD Medical Reference

Reviewed by David Zelman, MD on May 26, 2014
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