Table 1

Demographic factors and disease characteristics at presentation in children with JIA ever versus never breast fed

CharacteristicTotal cohortNever breast fedEver breast fedp Value (ever vs never breast fed)Univariate analysis of association between covariate and CHAQ >0.75 (OR, 95% CI)
N (%)923410 (44)513 (56)
Female, n (%)*604 (65)262 (64)342 (67)0.40.87 (0.61 to 1.23)*
Caucasian, n (%)*831 (90)381 (93)450 (88)0.0091.08 (0.65 to 1.80)*
Index of Multiple Deprivation category (n=737), n (%)*,†
 Low143 (20)37 (11)106 (26)<0.001Ref
 Medium334 (45)139 (43)195 (47)1.33 (0.86 to 2.06)
 High260 (35)149 (46)111 (27)1.76 (1.13 to 2.74)
Referral hospital, n (%)*
 Liverpool383 (42)183 (45)200 (39)<0.001Ref
 Manchester174 (19)83 (20)91 (18)0.91 (0.60 to 1.38)
 Glasgow139 (15)68 (16)71 (14)
 Newcastle50 (5)28 (7)22 (4)0.87 (0.45 to 1.68)
 London177 (19)48 (12)129 (25)1.07 (0.71 to 1.62)
Age at symptom onset (years), median (IQR)*6.4 (2.5, 11)7.6 (3.2, 11)5.7 (2.0, 10)<0.0010.97 (0.93 to 1.01)
Symptom duration at first visit (months), median (IQR)*5.6 (2.9, 12)5.6 (2.8, 13)5.6 (2.9, 11)0.61.00 (0.99 to 1.01)
Active joint count, median (IQR)2 (1, 5)2 (1, 5)2 (1, 5)0.6
Physician Global Assessment (100 mm VAS) (n=743), median (IQR)29 (16, 53)32 (18, 56)28 (15, 50)0.03
ESR (n=570), median (IQR)20 (6, 50)18 (6, 47)22 (7, 53)0.1
Parent global assessment (100 mm VAS) (n=656),median (IQR)21 (5, 50)39 (10, 64)23 (5, 50)<0.001
JADAS-71,‡ median (IQR), (n=340)*11 (6–18)13 (7–20)10 (6–17)0.021.10 (1.07 to 1.12)
Limited joint count, median (IQR)*1 (1, 3)1 (1, 3)1 (1, 3)0.31.09 (1.04 to 1.14)
Pain (100 mm VAS) (n=664), median (IQR)*30 (8, 58)29 (7, 54)18 (4, 45)<0.0011.04 (1.03 to 1.05)
CHAQ score (n=674), median (IQR)0.63 (0.13, 1.38)0.88 (0.25, 1.63)0.63 (0.13, 1.25)<0.001
% CHAQ >0.75 (n=674), n (%)303 (45)159 (54)144 (38)<0.001
ILAR subtype, n (%)*
 Systemic49 (5)23 (6)26 (5)0.05Ref
 Oligoarthritis (persistent)427 (46)189 (46)238 (46)0.56 (0.27 to 1.17)
 Oligoarthritis (extended)59 (7)28 (7)31 (6)1.19 (0.43 to 3.31)
 Polyarthritis (RF−)215 (23)79 (19)136 (27)1.69 (0.73 to 3.79)
 Polyarthritis (RF+)27 (3)11 (3)16 (3)2.36 (0.59 to 9.46)
 Enthesitis related52 (6)32 (8)20 (4)0.78 (0.29 to 2.10)
 Psoriatic67 (7)36 (8)31 (6)0.62 (0.24 to 1.57)
 Undifferentiated27 (3)12 (3)15 (3)0.47 (0.14 to 1.60)
OR (95% CI) CHAQ >0.75 in ever versus never breast fed (univariable)§ n=737 0.68 (0.48 to 0.95)
OR (95% CI) CHAQ >0.75 in ever versus never breast fed (adjusted)¶ n=7370.61 (0.39 to 0.95)
  • *Indicates variables included in multivariable logistic regression analysis.

  • †Indicates the number of children with the available measure when not present in all children.

  • ‡JADAS-71: composite score of 71 active joint count, Physician Global Assessment, parent general evaluation and ESR.

  • §AUC 0.55.

  • ¶AUC 0.84.

  • AUC, area under the curve; CHAQ, Childhood Health Assessment Questionnaire; ESR, erythrocyte sedimentation rate; ILAR, International League Against Rheumatism; JADAS, Juvenile Arthritis Disease Activity Score; JIA, juvenile idiopathic arthritis; Ref, reference; RF, rheumatoid factor; VAS, visual analogue scale.