Geographic Variation in Rheumatoid Arthritis Incidence Among Women in the United States

Abstract
Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology, characterized by chronic, destructive, debilitating arthritis that affects approximately 1% of the adult population.1 Both environmental and genetic factors seem important in determining RA susceptibility, and it is likely that they interact.2,3 Epidemiologic research points to environmental risk factors, including cigarette smoking,4-16 exogenous hormone use,17-25 female reproductive factors,26,27 occupational silica,28 and mineral oil29 as likely influences of RA risk.