Table 1 Characteristics of the 333 Swedish cases with RA and the 3334 cases with JIA
RAJIA
casescases
Total3333334
Sex
    Male811534
    Female2521800
Year of birth (median)19751980
Age at diagnosis/first discharge (median)233
Calendar period of inclusion
    1973–90517
    1980–901500
    1990–91451013
    2000–2188304
RF status
    Positive153–
    Negative107–
    Not specified73–

  • JIA, juvenile idiopathic arthritis; RA, rheumatoid arthritis; RF, rheumatoid factor.