The immune attack creates high levels of inflammation that destroy the joints and harm the heart, liver and other organs.

Despite extensive research, the cause of rheumatoid arthritis (RA) remains unknown. Scientists have learned much about the abnormal immune response and the mechanisms of inflammation over the years, but what triggers the disease process remain a mystery.

Most experts agree that a variety of environmental as well as genetic factors play a role. RA risk factors include the following:

1. Gender

Although both men and women can get RA, approximately 70 percent of people with RA are women.

2. Genetics

Researchers have found that people with several specific genetic markers are more likely to develop RA than those without the markers. Having a family member with RA also increases the chances of developing it, although most people with RA do not have a family history of it.

3. Obesity

People who are obese are 25 percent more likely to develop RA than those who are of normal weight.

4. Smoking

Studies show smoking can significantly increase the risk of RA. Although individual risk varies, heavy smokers have an increased risk that persists even decades after quitting.

5. Infection

Bacteria, viruses and other infectious agents may trigger the development of RA in someone who has a genetic predisposition for it.

There is no single laboratory test to confirm a diagnosis of RA. If your doctor thinks you might have RA, she will start by taking your medical history.

Detailed information about your symptoms might point to RA. The questions may include: Do you have pain in several joints? Do the same joints hurt on each side of your body? Do you experience stiffness in the morning? How long does the stiffness last? Are you often fatigued? Your doctor will conduct a physical exam and may ask you to fill out a questionnaire about your symptoms and daily function.

Seeking early treatment from a rheumatologist, a physician who has advanced training in arthritis and related musculoskeletal conditions, is your best first course of action in managing RA.