Rheumatoid arthritis in non-caucasian population: epidemiological data

Rheumatoid arthritis (RA) is a common autoimmune systemic inflammatory disease with still unknown cause. A robust hypothesis for the occurence of the disease is the result of an environmental exposure in a genetically susceptible individual. The risk of RA varies by ethnicity: the majority of the Caucasian populations reported a prevalence of 0.5 to 1% for this disease; higher prevalences were observed in American Indian tribes and lower ones, in countries of Africa and Asia. This regional variation in the prevalence of RA sustains the involvement of both genetic and enviromental factors in the occurence of this condition.