Rheumatoid Arthritis (cont.)
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What Causes Rheumatoid Arthritis?
Scientists still do not know exactly what causes the immune system to turn against itself in rheumatoid arthritis, but research over the last few years has begun to piece together the factors involved.
Genetic (inherited) factors: Scientists have discovered that certain genes known to play a role in the immune system are associated with a tendency to develop rheumatoid arthritis. For the genes that have been linked to rheumatoid arthritis, the frequency of the risky gene is only modestly higher in those with rheumatoid arthritis compared with healthy controls. In other words, individual genes by themselves confer only a small relative risk of disease. Some people who have these particular genes never develop the disease. These observations suggest that although a person's genetic makeup plays an important role in determining if he or she will develop rheumatoid arthritis, it is not the only factor. What is clear, however, is that more than one gene is involved in determining whether a person develops rheumatoid arthritis and how severe the disease will become.
Environmental factors: Many scientists think that something must occur to trigger the disease process in people whose genetic makeup makes them susceptible to rheumatoid arthritis. A viral or bacterial infection appears likely, but the exact agent is not yet known. This does not mean that rheumatoid arthritis is contagious: a person cannot catch it from someone else.
Other factors: Some scientists also think that a variety of hormonal factors may be involved. Women are more likely to develop rheumatoid arthritis than men. The disease may improve during pregnancy and flare after pregnancy. Breastfeeding may also aggravate the disease. Contraceptive use may alter a person's likelihood of developing rheumatoid arthritis. This suggests hormones, or possibly deficiencies or changes in certain hormones, may promote the development of rheumatoid arthritis in a genetically susceptible person who has been exposed to a triggering agent from the environment.
Even though all the answers are not known, one thing is certain: rheumatoid arthritis develops as a result of an interaction of many factors. Researchers are trying to understand these factors and how they work together.