Despite years of research and study, the precise cause of RA is not known. Physicians have determined that the pain, stiffness, and inflammation associated with this disease result from a disorder in the body's immune system. For unexplained reasons, the body's immune system—in the form of white blood cells and antibodies—attacks the joints and other tissues in the body. The continuous inflammation in the joints accounts for the damage of joints. What triggers this abnormal immune response remains unknown, although genetic factors and infectious/environmental agents have been the targets of the most study.
Genetic Factors
There appears to be a genetic component to RA. Nevertheless, although medical studies suggest that a person's genetic makeup is an important part of the story, it is not the whole answer.
For example, scientists have found that certain genes that play a role in the immune system are associated with a tendency to develop RA. The genes that influence this tendency are more common in the families of people who have RA. Although this “genetic tendency” to develop RA may be passed on to the next generation, the disease does not automatically occur in everyone who inherits the genes. At the same time, some people with RA do not have these particular genes. It is possible that the disease occurs only in people who have a genetic or inherited tendency toward the disease and who are also exposed to other “RA-causing agents.”
Environmental Factors
What causes an otherwise healthy person to develop RA? What triggers the immune system to attack the body? Many rheumatologists believe that an infectious agent is the trigger that produces RA in individuals who have an underlying genetic susceptibility to the disease. An infectious agent such
as a virus or bacterium may be responsible, but the exact agent is not yet known, despite exhaustive studies.
Other Causes
Why does RA occur more frequently in women than in men? Why does RA occur more frequently in adults than in children? Could hormones have some effect on the development of RA? Some scientists think so. They suggest that hormones, or possibly deficiencies or changes in certain hormones, may promote the development of RA in a person with “RA-prone genes”who has been exposed to a triggering agent from the environment.
After decades of study, scientists don't have all the answers about what causes RA, though most believe that RA develops as a result of an interaction of many factors. In addition to identifying possible causes of this disease, researchers have been able to exclude certain agents as causes of RA. According to scientific evidence now available, RA is not caused by any of the following factors:
- Environments that are cold and damp
- Changes in weather or ambient air pressure
- Diet—especially a lack (or excess) of vitamins or any other dietary elements such as fats, sugars, acids, or metals
- Exposure to mercury, arsenic, or other heavy metals
- Faulty absorption or elimination of substances from the bowel
- Infections in the internal organs of the body
- Exposure to radiation or magnetic fields
- The effects of mold or yeast in the environment or in the blood
If you have further questions regarding the causes of RA, discuss them with your rheumatologist, who is an expert in that area.