Rheumatoid arthritis (RA) is an autoimmune disease. In people with RA, the immune system attacks the lining of the joints. This causes joint symptoms, including:
- loss of function
People with RA may also have symptoms affecting other tissues.
Doctors don’t know why people develop RA. According to the American Academy of Orthopaedic Surgeons, researchers suspect a combination of genetic susceptibility and other factors. Some doctors think RA may be caused by an inappropriate response to an infection.
However, no one really knows what makes the immune system turn against the body. Although doctors don’t yet understand the cause of RA, they have identified certain risk factors for the disease.
According to the Centers for Disease Control and Prevention (CDC), RA is two to three times more common in women than men. In general, autoimmune diseases are more common in women than men. However, some of the increased risk of RA may also be due to hormonal factors.
The relationship between hormones and RA is not yet understood. However, there are several strong pieces of evidence that female hormones are related to RA symptoms. For example, the CDC states that RA is less common in women who have:
- used oral contraceptives
- a history of breastfeeding
- had a live birth
- regular menstrual periods
The majority of RA diagnoses are made in adults in their 60s. Some people do develop RA as children or as younger adults. However, RA in young people is rare.
According to the Mayo Clinic, you are more likely to be diagnosed with RA if a member of your family has it.
Several genes have been associated with RA. However, RA is not an inherited condition like some other genetic diseases. Even someone who has an identical twin with RA will not necessarily get the disease. Instead, it’s thought that genetics affect a person's susceptibility to RA triggers.
Cigarette smokers are more likely than nonsmokers to develop RA. Quitting smoking can reduce this risk.
Smokers who are diagnosed with RA also tend to have more severe symptoms, and they are more difficult to treat effectively.