Table 1 Descriptive characteristics at baseline of participants who completed the study (n =!3). Values are mean (standard deviation) unless otherwise indicated

Age (years)

13.0(2.0)

13.5 (2.3)

12.4(1.6)

Ethnicity (tt Asian/Caucasian/ Other)

3/8/2

1/5/1

2/3/ 1

Tanner stage (# 1/2/3/4/5)

3/3/4/2/1

1 /2/3/1/0

2/ 1/1/ 1/1

Maturity offset (years)

0.07(1.8)

1.0 (1.9)

−1.0 (1.0)

Height (cm)

149.7(8.3)

150.0(9.6)

149.4 (7.4)

Height z-score

−0.61 (0.83)

−0.80(0.%)

−0.39 (0.66)

Weight (kg)

42.6(7.0)

41.1 (43.9)

41.1 (5.0)

Weight z-score

−0.39 (1.26)

−0.48(1.21)

− 0.28 (1.42)

BMI (kg/m²)

18.8(2.6)

19.4 (2.2)

18.5(3.1)

BMI z-score

−0.07 (1.26)

0.02(0.87)

−0.19 (1.69)

Time since diagnosis (months)

57 (47)

78 (23)

34 (49)

JIA subtvpes - polyarticular course

4 (2 poly RF negative, 2 oligo extended)

3 (2 poly RF negative, 1 oligo extended)

1 (oligo extended)

JIA subtypes - oligoarticular course

9 (2 oligo persistent. 3 ERA. 2 psoriatic, 2 undi fterentiated)

4 (2 psoriatic, 1 oligo persistent, 1 undifferentiated)

5 (3 ERA, 1 oligo persistent, 1 undifferentiated)

Medications (n)

7 NSAIDS,9 DMARDs, 4 Biologies

5 NSAIDS, 6 DMARDs, 3 biologies

2 NSAIDS, 3 DMARDs, 1 biologic

Fracture history

4

1 distal radius, 1 nasal

1 distal radius, 1 distal tibia

Dietary calcium intake (mg)

740 (410)

468 (196)

1058 (364)