Table 1

Characteristics of patients with JIA and general population individuals, and of cancer cases (all sites) in patients with JIA and general population individuals

VariablesPatients with JIAGeneral population (matched)
All individuals
 Number of subjects (% girls)6721 (64)33 774 (64)
 Start of follow-up (number of subjects, % of total)
 2001–20031335 (20)6695 (20)
 2004–20071971 (29)9958 (29)
 2008–20111646 (24)8259 (24)
 2012–20161769 (26)8862 (26)
 Median age (years) at start of follow-up (p25–p75)10 (5–13)10 (5–13)
Cases with cancer
 Number of cancer cases
 (% with lymphoproliferative malignancies)
10 (50)35 (20)
 Median age (in years) at cancer diagnosis
 (p25–p75)
11.7 (9.4–14.0)13.6 (9.4–15.8)
 Median follow-up time (in years) until cancer diagnosis
 (p25–p75)
2.1 (0.4–3.3)3.9 (1.1–5.9)
  • JIA, juvenile idiopathic arthritis; p25, percentile 25; p75, percentile 75.