Demographic and clinical characteristics according to length of breast feeding*
| Characteristic† | Never | <3 months | ≥3 and <6 months | ≥6 months | p Value for trend |
|---|---|---|---|---|---|
| N (%) | 410 (46) | 233 (26) | 124 (14) | 131 (15) | |
| Female, n (%) | 262 (64) | 154 (66) | 85 (69) | 90 (69) | 0.2 |
| Caucasian, n (%) | 381 (93) | 208 (89) | 113 (91) | 111 (85) | 0.01 |
| Index of Multiple Deprivation (n=737), n (%) | |||||
| Low | 37 (11) | 44 (23) | 26 (27) | 34 (32) | <0.001 |
| Medium | 139 (43) | 93 (48) | 45 (48) | 47 (45) | |
| High | 149 (46) | 57 (29) | 25 (25) | 24 (23) | |
| Age at symptom onset (years), median (IQR) | 7.5 (3.4, 11.5) | 6.0 (2.5, 10.4) | 5.0 (1.9,. 9.7) | 4.8 (2, 9.9) | 0.002 |
| Symptom duration (months), median (IQR) | 5.6 (2.8, 12.5) | 5.5 (2.9, 10.3) | 5.3 (2.9,. 14.3) | 5.3 (2.9, 14.3) | 0.5 |
| Active joint count, median (IQR) | 2 (1, 5) | 2 (1,. 6) | 2 (1, 4) | 2 (1, 6) | 0.4 |
| Limited joint count, median (IQR) | 1 (1, 3) | 1 (1, 3) | 1 (0, 3) | 1 (1, 3) | 0.08 |
| Physician global assessment (n=743), median (IQR) | 32 (18, 56) | 30 (18, 57) | 25 (12, 46) | 24 (13, 49) | 0.005 |
| ESR (n=570), median (IQR) | 18 (6, 47) | 20 (6, 50) | 29 (7, 55) | 21 (9, 53) | 0.1 |
| CHAQ score (n=674), median (IQR) | 0.88 (0.25, 1.63) | 0.63 (0.13, 1.25) | 0.63 (0.13, 1.25) | 0.5 (0, 1.13) | <0.001 |
| CHAQ >0.75 (n=674), n (%) | 136 (46) | 63 (39) | 35 (41) | 39 (37) | 0.001 |
| Parent general evaluation. (100 mm VAS) (n=656), median (IQR) | 39 (10, 64) | 16 (3, 45) | 27 (4, 50) | 17 (5, 42) | 0.008 |
| Pain (100 mm VAS) (n=664), median (IQR) | 29 (7, 54) | 22 (4, 53) | 28 (5, 60) | 20 (6, 45) | 0.005 |
| JADAS-71, median (IQR) | 13.2 (7–19.9) | 10.4 (5.9–16.9) | 10.2 (5–21.3) | 10.6 (4.5–15.6) | 0.1 |
| ILAR Subtype, n (%) | |||||
| Systemic arthritis | 23 (6) | 8 (4) | 9 (7) | 7 (5) | 0.09 |
| Oligoarthritis (persistent) | 189 (46) | 101 (43) | 64 (51) | 59 (45) | |
| Oligoarthritis (extended) | 28 (7) | 13 (6) | 10 (8) | 6 (4) | |
| Polyarthritis (RF negative) | 79 (19) | 73 (31) | 22 (18) | 38 (29) | |
| Polyarthritis (RF positive) | 11 (3) | 8 (3) | 5 (4) | 2 (2) | |
| Enthesitis-related arthritis | 32 (8) | 11 (5) | 4 (3) | 4 (3) | |
| Psoriatic arthritis | 36 (9) | 12 (5) | 8 (7) | 10 (8) | |
| Undifferentiated arthritis | 12 (3) | 7 (3) | 2 (2) | 5 (4) | |
*Duration of breast feeding not reported for 25 children.
†Numbers in brackets in first column indicate available data where data items were missing or not available.
CHAQ, Childhood Health Assessment Questionnaire; ILAR, International League Against Rheumatism; JADAS, Juvenile Arthritis Disease Activity Scores; RF, rheumatoid factor.