About 1% of the population is affected, although we have no accurate prevalence figures for South Africa.
Women are affected about two to three times more often than men. The incidence increases with age, and the sex difference diminishes in older people. Rheumatoid arthritis is seen around the world and all races are affected.
It can start at any age and often affects young people. The peak onset is in the 4th and 5th decade, with 80% of people developing the disease between the ages of 35 and 50.
There is a strong genetic predisposition: severe rheumatoid arthritis is found at four times the expected rate in first-degree relatives of people with the disease.
Causes of rheumatoid arthritis
Symptoms of rheumatoid arthritis