Bone mineral density and explanatory factors in children and adults with juvenile dermatomyositis at long term follow-up; a cross sectional study

Table 2 BMD and Z scores in JDM patients and controls in total, <20y and ≥ 20y

Variable	Patients (n = 59)	Controls (n = 59)	Patients <20y (n = 28) ≥20y (n = 31)	Controls <20y (n = 28) ≥20y (n = 30–31)	p-values
BMD, g/cm²
Whole body	1.10 (0.15)	1.13 (0.14)			0.05
Age < 20y			1.01 (0.13)	1.06 (0.16)	0.02
Age ≥ 20y			1.18 (0.10)	1.19 (0.08)	0.71
Lumbar spine, L2-L4	1.12 (0.23)	1.17 (0.22)			0.07
Age < 20y			0.99 (0.21)	1.07 (0.27)	0.04
Age ≥ 20y			1.24 (0.18)	1.26 (0.11)	0.52
Total hip
Age ≥ 20y			1.00 (0.18)	1.05 (0.14)	0.10
Ultra distal radius
Age ≥ 20y			0.48 (0.08)	0.5 (0.08)	0.13
Forearm
Age ≥ 20y			0.87 (0.09)	0.93 (0.11)	0.01
Z-score
Whole body	−0.07 (1.08)	0.27 (0.90)			0.06
Age < 20y			−0.39 (0.99)	0.28 (1.01)	0.01
Age ≥ 20y			0.21 (1.10)	0.26 (0.71)	0.83
Lumbar spine, L2-L4	−0.16 (1.2)	0.4 (1.02)			0.07
Age < 20y			−0.39 (1.01)	0.25 (1.21)	0.04
Age ≥ 20y			0.06 (1.34)	0.24 (0.84)	0.56
Total hip
Age ≥ 20y			−0.32 (1.35)	0.14 (0.99)	0.10
Ultra distal radius
Age ≥ 20y			−0.42 (1.36)	0.16 (1.33)	0.13
Forearm
Age ≥ 20y			−0.76 (1.03)	−0.05 (0.87)	0.01
T-score
≥ 20y
Whole body	NA	NA	0.16 (1.25)	0.29 (0.82)	0.81
Lumbar spine, L2-L4	NA	NA	0.00 (1.44)	0.25 (0.92)	0.09
Total hip	NA	NA	0.42 (1.41)	0.07 (1.04)	0.07
Ultra distal radius	NA	NA	−0.43 (1.35)	0.14 (1.35)	0.48
Forearm	NA	NA	−0.77 (1.00)	−0.07 (0.87)	0.38

BMD bone mineral density, y years. Values for total hip, ultra distal and forearm are not applicable for age < 20y. Values are mean (SD). p-values when comparing patients and controls using paired samples t-test

ISSN: 1546-0096