Rheumatoid arthritis

Rheumatoid arthritis is an autoimmune disease characterized by pain, swelling and deformity of the joints due to prolonged inflammation, even leading to disability. It can affect any joint, although it is most common in wrists and hands. In some people, the condition can damage different systems such as the skin, eyes, lungs or blood vessels.

The causes of rheumatoid arthritis are unknown, although the complex contribution of genetics together with environmental factors such as certain viral infections or hormones has been proposed. Even intestinal flora has been implicated in its development.

The prevalence of rheumatoid arthritis is about 1% in the general population, although it is more frequent in women than in men. Among the non-genetic risk factors that may contribute to the development of the disease are:

  • Age: it can appear at any age, but the incidence increases with age.
  • Sex: it is 2-3 times more frequent in women than in men.
  • Smoking: Smokers have a higher risk of developing the disease.
  • Obesity.

Rheumatoid arthritis (RA) is a disease of complex etiology for which twin studies estimate a 60% genetic contribution to the disease. In an association study conducted with about 23000 cases and more than 300000 controls, more than 70 loci significantly associated with the disease are shown. The RA variants were preferentially located in binding sites of various transcription factors related to CD4+ T cell biology and, to a lesser extent, other cells of the immune system.


Rheumatoid arthritis is an autoimmune disease that causes pain, stiffness, swelling and loss of joint mobility, especially in the hands, feet, wrists, shoulders, elbows, hips and knees. Occasionally it can cause fatigue, fever and loss of appetite. These symptoms may be constant or come and go, with active periods (flares) and others of relative remission.

About 40% of affected individuals have symptoms involving other systems such as the skin, eyes, lungs, kidneys, etc.

Rheumatoid arthritis is the most disabling of the rheumatic diseases.


Because it is a disease of unknown origin, there is no sure way to prevent rheumatoid arthritis, however, there are actions that could help to have a better management of the pathology such as:

  • Lead a healthy lifestyle, with moderate physical activity and healthy eating.
  • Avoid activities that require heavy physical efforts such as standing for long hours or avoiding bending the back and neck for hours at a time.
  • Reduce body weight in case of overweight.
  • Avoid consumption of toxic substances such as tobacco.

Number of observed variants

13.5 million variants

Number of risk loci analyzed in the study

73 loci


Ha E, Bae SC, Kim K . Large-scale meta-analysis across East Asian and European populations updated genetic architecture and variant-driven biology of rheumatoid arthritis, identifying 11 novel susceptibility loci. Annals of the Rheumatic Diseases. 2021 May;80(5):558-565.

Mayo clinic [March 2022]

Giannini D, Antonucci M, Petrelli F, Bilia S, Alunno A, Puxeddu I. One year in review 2020: pathogenesis of rheumatoid arthritis. Clin Exp Rheumatol. 2020 May-Jun;38(3):387-397.

Smolen JS, Aletaha D, Barton A, Burmester GR, Emery P, Firestein GS, Kavanaugh A, McInnes IB, Solomon DH, Strand V, Yamamoto K. Rheumatoid arthritis. Nat Rev Dis Primers. 2018 Feb 8;4:18001.

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