Table 1 Characteristics of JIA patients with and without a family history of AD in parents (n = 8673)

Female, n (%)

5060 (68.0%)

847 (68.8%)

Age at JIA onset, median (IQR)

5.2 (2.4–9.8)

6.3 (2.5–10.8)

Geographic region, n (%)

 Central and Eastern Europe

2091 (28.1%)

210 (17.1%)

 Latin America

663 (8.9%)

50 (4.1%)

 Northern Africa and Middle East

157 (2.1%)

44 (3.6%)^{b, c}

 Scandinavia

685 (9.2%)

177 (14.4%)^{b, c}

 Southern Asia

153 (2.1%)

16 (1.3%)^{d, e}

 Southern Europe

2384 (32.0%)

497 (40.4%)^{b, c}

 Western Europe

1309 (17.6%)

237 (19.3%)^{b, c, e}

Ethnicity, n (%)

 European Caucasian

5654 (85.6%)

1008 (89.1%)

 Hispanic

267 (4.0%)

21 (1.9%)^f

 Indian

132 (2.0%)

12 (1.1%)

 Multiethnic

93 (1.4%)

14 (1.2%)

 Northern African or Middle Eastern

281 (4.3%)

60 (5.3%)^g

 Southeast Asian

59 (0.9%)

6 (0.5%)

 Sub-Saharan African

75 (1.1%)

5 (0.4%)

 Other

47 (0.7%)

n = 6608

5 (0.4%)

n = 1131

ILAR category, n (%)

 ERA

777 (10.4%)

178 (14.5%)

 Oligoarthritis

2934 (39.4%)

319 (25.9%)^h

 Polyarthritis RF-

2045 (27.5%)

228 (18.5%)^h

 Polyarthritis RF+

335 (4.5%)

38 (3.1%)^h

 Psoriatic arthritis

144 (1.9%)

146 (11.9%)^{h, i, j, k}

 Systemic arthritis

898 (12.1%)

51 (4.1%)^{h, i, j, l}

 Undifferentiated arthritis

309 (4.2%)

271 (22.0%)^{h, i, j, k, m}

 ANA positive

2853 (40.9%)

n = 6970

514 (44.3%)

n = 1160

 RF positive)

356 (5.4%) n = 6629

49 (4.5%)

n = 1088

 HLA-B27 positive

865 (19.4%)

n = 4467

229 (28.6%)

n = 800

 Active joints at study entry

0 (0–2)

n = 3143

0 (0–2)

n = 583

cJADAS at study entry

2.0 (0.0–7.0)

n = 2713

2.0 (0.0–7.0)

n = 519

 Active joints at last visit

0 (0–1)

n = 3143

0 (0–1)

n = 583

cJADAS at last visit

1.0 (0.0–5.0)

n = 2713

1.0 (0.0–5.0)

n = 519

Observation period in years, median (IQR)

4.0 (1.8–7.3)

3.9 (1.8–7.0)