Rheumatoid arthritis (referred to as RA in short) is a unique disorder, in the sense that, it is caused by the wrong response of the autoimmune system of our body itself.

In other words, rheumatoid arthritis is an autoimmune disease caused by the body’s own immune system mistakenly attacking the body’s own tissues.

The autoimmune system is the mechanism, which acts as a defense force of our body, protecting it from external invasive forces (e.g. bacteria). This condition is thus a result of our own autoimmune system.


Rheumatoid arthritis is a chronic, progressive inflammatory disorder, which commonly attacks the smaller synovial joints of the hands and feet (fingers, wrists, feet, and ankles), and can cause synovitis and erosion of the cartilage of the joints.

Typically, in RA the same joints are involved on both sides of the body.

Sometimes, bigger joints like the shoulder and knees can also get involved. This inflammatory process can affect more than just your joints. This condition can damage a wide variety of body systems, including the lungs, heart, skin, eyes, and blood vessels.

Unlike the wear-and-tear damage of osteoarthritis, rheumatoid arthritis damages the lining of your joints. It causes symptoms of pain and swelling of the joints that can ultimately result in bone erosion and joint deformity.

Rheumatoid arthritis is commonly seen more after the age of 40 years and with a 2.5 higher prevalence in women than in men. About 1.5 million people suffer from RA in the United States.

It affects 0.5 to 1% of the population in the developed world. Between 5 to 50 of 100,000 people newly develop this condition.

Rheumatoid arthritis causes

Your immune system normally protects your body from infection and diseases. In rheumatoid arthritis, the autoimmune mechanism turns rogue (sort of) and inadvertently attacks the synovial membrane (synovium) of the joints though it is healthy and normal.

The synovial membrane is the soft tissue found between the joint capsule and the joint cavity of the synovial joints.

As a result, the synovium becomes thickened and inflamed. Eventually, if the inflammation is left untreated, the autoimmune reaction destroys the cartilage and the surrounding bones within the joint.

Consequently, the ligaments and the tendons that are attached to the bones of the joint weaken and become loose. Over time, the joint loses its alignment, shape, and function.

Therefore, once the diagnosis of RA is established through the blood tests and imaging procedures, you must take prompt treatment, which aims to give relief from symptoms and town down the overactive immune system.

However, what causes rheumatoid arthritis is still unknown. A genetic factor does seem likely, which can make you more prone to rheumatoid arthritis due to environmental factors such as infection by bacteria and viruses when the autoimmune system becomes active.

According to the Arthritis Foundation:

“Researchers have shown that people with a specific genetic marker called the human leukocyte antigen (HLA) DRB1 gene (HLA shared epitope) have a fivefold greater chance of developing rheumatoid arthritis than do people without the marker.”

RA risk factors

Research is still incomplete about the causes and the risk factors that can lead to rheumatoid arthritis, but some headway is being made. Factors that may increase your risk of rheumatoid arthritis include:

  • Sex. Women are more prone than men to developing rheumatoid arthritis.
  • Age. Rheumatoid arthritis can develop at any age, but it is seen to occur most commonly in middle age.
  • Family history. If an immediate member of your family has rheumatoid arthritis, you are at an increased risk of the disease.
  • Excess weight. People who are overweight or obese appear to be at a somewhat higher risk of developing rheumatoid arthritis.
  • Cigarette smoking. A number of detailed studies have shown that cigarette smoking carries a considerable risk of developing this disease and further its severity particularly if you are genetically prone. This risk becomes stronger in individuals who carry the shared epitope and more pronounced in individuals who carry the RA autoantibodies. Smoking is also associated with the greater severity of this disease.
  • Oral bacteria. Another finding in recent years is the association between rheumatoid disease and periodontal disease. Periodontal disease, including periodontitis, is the infection of the gums and the tissues that surround the teeth and support them. Periodontitis can cause slow destruction of the alveolar bone around the teeth and of the collagen matrix. It is now established that a specific species of bacteria, Porphyromonas gingivalis, which causes periodontal disease contains an enzyme that can cause citrullination of proteins. Citrullination of proteins is the preceding process of the autoimmune response that leads to RA. This link strongly suggests that periodontal infection can lead to rheumatoid arthritis in some people, leading researchers to study this angle more deeply.