About 1% of the population is affected by rheumatoid arthritis (RA), although there are no accurate prevalence figures for South Africa.
Women are affected about three times more often than men are. The incidence increases with age and the difference in incidence between men and women diminishes in older people. In other words, while more younger women have RA, it’s not at all uncommon in older men.
Rheumatoid arthritis is found in people across the world, and it’s a disease that affects all races. It can start at any age and often affects young people. Four in every five people who develop the disease are between the ages of 35 and 50.
There’s a strong genetic predisposition: severe rheumatoid arthritis is found at four times the expected rate in first-degree relatives of people with the disease. But at the same time, many people with RA have no family history of the disease. The fact that many people who are genetically predisposed to the disease never develops RA points to the strong likelihood that genes are only one of the reasons why RA develops.
Although not direct causes of the disease, RA tends to be more common among people who smoke.
Reviewed by Dr Stella Botha, rheumatologist at Groote Schuur Hospital, Cape Town (MBChB, MRCP, PhD), November 2017.