The underlying causes for many types of arthritis are unknown. For some types of arthritis, such as gout and pseudogout, the underlying causes are easy to determine: uric acid crystals in the case of gout, and calcium pyrophosphate crystals in the case of pseudogout. Infectious arthritis can also be determined by the presence of bacteria, viruses, or even a fungus.
Genetics seem to play a large role in many types of arthritis, including gouty, rheumatoid, and osteoarthritis (degenerative joint disease). If a close family member has or had a certain type of arthritis, you are more likely to have it.
As with many diseases, no single cause for arthritis may ever be found; it may be the result of a combination of factors. Lifestyle factors play an important role in all types of arthritis. (See Treatment Modalities
for more detail.) Good diet and exercise can be helpful in fighting the onset of arthritis, whereas smoking, alcohol use, obesity and more all appear to have a great impact on whether an individual will have arthritis, especially the types that are chronic in nature.
Osteoarthritis (Degenerative Joint Disease)
The cause of osteoarthritis was once thought to be simply degenerative. The more you use a joint, the more it’s subject to wear and tear. This appears not to be the case, as many long distance runners are no more likely to have osteoarthritis than the rest of the population.
Scientists now think that there might be some genetic component to osteoarthritis, as siblings and twins are more likely to share the disease. The loss of the cartilage cushion between bones is the main feature of the disease, but determining just why some people lose that cushion and others don’t is a bit of a mystery and may be determined by future research.
The destruction of the joint in rheumatoid arthritis (autoimmune) is the result of the body attacking itself. The immune system is designed to attack foreign invaders in the body. For reasons not completely clear, when someone has rheumatoid arthritis the body thinks the joints are foreign invaders. When the body attacks its own joints, the result is pain and inflammation. This inflammation eventually leads to the destruction of the joint.
Like many autoimmune diseases, rheumatoid arthritis tends to run in families. This suggests that genetics play a role in the development of the disease.