Rheumatoid Arthritis Causes

There is no known cause of rheumatoid arthritis, but years of research suggest that a combination of genetic, environmental, and hormonal factors is responsible.

Genetic Causes of Rheumatoid Arthritis

The specific gene associated with rheumatoid arthritis, HLA-DR4, is found in more than two-thirds (67 percent) of Caucasians with the disease. In contrast, it is only found in 20 percent of the general population. While presence of this specific genetic marker increases the likelihood of developing rheumatoid arthritis, it is by no means an accurate diagnostic tool. In fact, most physicians do not order this test when diagnosing rheumatoid arthritis.

One way genetics may contribute to the development of rheumatoid arthritis is through the control of immune system responses. In a healthy individual, white blood cells produce antibodies directed against the millions of pathogens individuals are exposed to on a daily basis. Rheumatoid arthritis is classified as an autoimmune disorder, which means the white blood cells are mistakenly directed to produce antibodies against the body’s own healthy tissues in addition to outside pathogens.

Environmental Links to Rheumatoid Arthritis

One of the greatest environmental risk factors for rheumatoid arthritis is smoking (specifically, nicotine). While the direct effect of smoking is not fully understood, it is believed that prolonged smoking plays a role in increasing the concentration of rheumatoid factor, which in turn causes malfunction in the immune response.

Some scientists also believe the disease can be triggered by a viral or bacterial infection, but there is currently no proof for this hypothesis.

Hormonal Factors

The higher prevalence of rheumatoid arthritis in women can be linked to both environmental and hormonal factors. For instance, oral contraceptives, which may contain doses of the hormone progestin or a combination of progestin and estrogen, have been correlated with a woman’s likelihood of developing rheumatoid arthritis. The disease has also been shown to improve during pregnancy, only to flare up again after the baby is born. Breastfeeding can also sometimes make symptoms worse.

While the exact cause is poorly understood, it is clear that persons with a genetic predisposition who are also exposed to a harmful environmental factor or experience significant disruptions in hormonal balance are the most susceptible.