Table 1.

Demographic and clinical characteristics of schoolchildren according to the presence of antinuclear antibodies (ANA) or musculoskeletal pain (MSP).

CharacteristicsInitial Cohort, n (%)Subjects with MSP at Baseline, n (%)Subjects ANA+ at Baseline, n (%)
In 2009, n = 261In 2009, n = 77In 2012, n = 67In 2009, n = 32In 2012, n = 28
Lost to followup10 (13.0)4 (12.5)
Female:male1:1.11:1.51:1.41:1.11:1.1
Mean age, yrs (range)10.6 (8–13)10.8 (8–13)14 (11–16)10.5 (8–13)13.4 (11–16)
MSP77 (29.5)77 (100.0)37 (55.2)17 (53.1)11 (39.3)
ANA+32 (12.3)10 (13.0)30 (44.8)32 (100.0)26 (92.9)
Titer
  1:8022 (8.4)6 (7.8)17 (25.4)22 (68.8)5 (17.9)
  1:1608 (3.1)3 (3.9)6 (8.9)8 (25.0)7 (25.0)
  1:3201 (0.4)0 (0.0)4 (5.9)1 (3.1)10 (35.7)
  1:6401 (0.4)1 (1.3)3 (4.5)1 (3.1)4 (14.3)
Pattern
  Nuclear fine speckles12 (37.5)4 (40.0)23 (76.7)12 (37.5)14 (53.8)
  Homogeneous10 (31.3)2 (20.0)5 (16.7)10 (31.3)4 (15.4)
  Nuclear coarse speckles5 (15.6)2 (20.0)2 (6.6)5 (15.6)5 (19.2)
  Nucleolar3 (9.4)1 (10.0)0 (0.0)3 (9.4)2 (7.7)
  Centriolar1 (3.1)0 (0.0)0 (0.0)1 (3.1)1 (3.9)
  Multiple nuclear dots1 (3.1)1 (10.0)0 (0.0)1 (3.1)0 (0.0)
Prepubertal subjects184 (70.5)64 (83.1)22 (32.8)25 (78.1)11 (39.3)
Pubertal subjects77 (29.5)13 (16.9)45 (67.2)7 (21.9)17 (60.7)
Family history of autoimmune diseases17 (6.5)4 (5.2)5 (7.1)3 (9.4)4 (14.3)