ABSTRACT
Rheumatoid arthritis (RA) is a chronically progressive, systemic, autoimmune inflammatory disease. The primary target of the disease is synovium.
INCIDENCE AND DEMOGRAPHICS n 1% of population affected, but varies in subpopulations n 6% of Pima Indians affected n More common in women than men at 2:1 to 3:1 ratio n Onset in third to sixth decade
ETIOLOGIC FACTORS n RA is idiopathic. n Twin studies show 20% concordance in identical twins, 5% concordance in fraternal twins.
