Session Information
Session Type: ACR Concurrent Abstract Session
Session Time: 11:00AM-12:30PM
Background/Purpose: JDM presents with proximal muscle weakness and atrophy is frequent. Still, body composition (BC) in JDM has not been widely studied, but is known to be unfavourably altered in other CTDs and associated with physical disability. It has also been proposed that monocyte chemoattractant protein-1 (MCP-1), acting as a myokine, may promote inflammation in skeletal muscle in idiopathic inflammatory myopathies. Aim of study was to compare BC and myokines in JDM patients with controls and explore associations between measures of BC and myokines with physical function outcomes.
Methods: 59 JDM patients and 59 age- and sex-matched controls were included. BC including total and appendicular lean mass (LM) and fat mass (FM), was measured by DXA. MCP-1 and IL-6 in serum were quantified. Functional outcomes were short form-36 physical component summary (SF-36), childhood or adult HAQ (CHAQ/HAQ), manual muscle testing (MMT-8) and 6 minute walking test distance (6 MWD). Multiple linear backward regression was used to identify indicators of appendicular lean mass (ALM) and appendicular fat mass percentage (AFM%) and to assess associations between physical function outcomes and ALM, AFM% and myokines.
Results: Table 1 presents characteristics, BC and myokine levels in patients and controls. Median disease duration was 16.8 years; 61% were female; 28% were on prednisolone or DMARDs at follow-up. Patients had significantly higher ESR, lower SF-36, MMT-8, 6 MWD, and physical activity than controls.
BMI was comparable in patients and controls (P=0.752). Patients had 8% lower total lean mass, 10.4% lower appendicular LM and 6% lower trunk LM compared to controls (all P’s ≤0.032). Total body FM% was 10.6% higher, AFM% was 10.6% % higher and android:gynoid fat ratio was 34.3% higher in patients than controls (all P’s ≤0.017). MCP-1 and IL-6 were higher in patients than controls (P’s ≤0.017).
In JDM patients, MCP-1 was an independent indicator of ALM (ß=-0.041, 95%CI(-0.081, -0.001)) and CRP and DAS muscle independent indicators of AFM% (ß=0.8, 95%CI (0.3, 1.3); ß=1.3, 95%CI(0.3, 2.2)).
When identifying independent indicators of physical outcomes, ALM was associated with SF-36 and MMT-8 (ß=0.6, 95%CI(0.1, 1.0); ß=0.370, 95% CI(0.190-0.550)); AFM% with CHAQ/HAQ, MMT-8 and 6MWD (ß= -0.005, 95%CI(0.001, 0.009); ß=-0.132, 95%CI(-0.203, -0.062); ß=- 1.968, 95%CI (-2.931, -1.006)) and MCP-1 with CHAQ/HAQ and 6MWD (ß=0.004, 95%CI(0.001, 0.008) and ß=-1.512, 95%CI(-3.264, -0.241)).
Conclusion: JDM patients assessed after long-term disease duration had unfavorable alterations in BC compared with controls, including lower LM and higher FM percentage. MCP-1 was higher in patients compared with controls, and independently associated with lower ALM and poorer functional outcomes in patients. Low ALM and high AFM percentage were also independently associated with impaired physical function in patients.
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Table 1. Characteristics and body composition data in JDM patients and controls. |
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JDM patients total (n=59)
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Controls (n=59)
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P-value
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Age, years at FU
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21.5 (15.4-34.8) |
21.6(15.1-34.8) |
0.413 |
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DAS muscle at FU
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1.0 (0.0-2.0) |
NA |
NA |
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DAS skin at FU
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4.0 (2.0-5.0) |
NA |
NA |
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Physical exercise, hours/week (n=51)
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4.0 (3.0-4.0) |
5.0(3.5-5.0) |
0.017 |
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hs-CRP, ug/mL
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0.98(0.28-2.54) |
0.59(0.23-1.25) |
0.183 |
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ESR, mm (n=55)
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6.0(3.0-9.5) |
4.00(3.00-8.00) |
0.025 |
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CHAQ/HAQ
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0.0 (0.0-0.3) |
NA |
NA |
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SF-36 PCS >13 years (n=51)
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53.9 (46.4-58.2) |
56.9 (52.8-59.7) |
0.018 |
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MMT-8
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78 (75-80) |
80 (80-80) |
<0.001 |
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6MWD, m (n=58)
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592.3 (80.6) |
649.4 (78.8) |
<0.000 |
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Antropometric parameters
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Weight, kg
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62.6 (20.1) |
64.9(19.9) |
0.383 |
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Height, cm
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165.5 (15.0) |
167.5 (15.9) |
0.095 |
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BMI, kg/m2
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22.3 (4.8) |
22.5 (4.5) |
0.752 |
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DXA-derived measures
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Total body LM, kg
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41.3 (12.9) |
44.9 (13.6) |
0.008 |
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ALM, kg
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18.1 (6.5) |
20.2 (6.9) |
0.004 |
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Trunk LM, kg
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20.5 (6.28) |
21.8 (8.65) |
0.032 |
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LMI, kg/m2
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14.69 (2.53) |
15.56 (2.63) |
0.014 |
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ALMI, kg/m2
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6.39(1.43) |
6.96 (1.50) |
0.006 |
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Total body FM, kg
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19.4 (9.2) |
18.0 (8.2) |
0.364 |
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AFM, kg
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9.0 (4.0) |
8.6 (3.4)
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0.528 |
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Total body FM percentage
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31.2 (7.9) |
28.2 (7.5) |
0.017 |
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Trunk FM percentage
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29.9 (9.7)
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27.0 (9.0)
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0.082 |
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AFM percentage
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33.3 (9.5)
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30.1 (8.1)
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0.010 |
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Android:gynoid fat ratio
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0.49 (0.36)
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0.36 (0.16)
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0.008 |
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Myokines
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IL-6, pg/mL (n=54)
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3.91 (3.17-5.74)
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3.56 (2.53-4.49)
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0.017
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MCP-1, pg/mL (n=54)
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34.69 (21.88) |
25.34 (11.45) |
0.006 |
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Values are mean (SD) or median(IQR) or number(%); n: =59 pairs of patients and controls, or n=59 patients, unless otherwise stated. AFM, appendicular fat mass; ALM, appendicular lean mass; ALMI, appendicular lean mass index; BMI, body mass index; CHAQ/HAQ, child and adult health assessment questionnaire; hs-CRP, high sensitive c-reactive protein; DAS, disease activity score for JDM; DXA, dual x-ray absorptiometry; ESR, erythrocyte sedimentation rate; IL-6, interleukine 6; LM, lean mass; LMI, lean mass index; MCP-1, monocyte chemoattractant protein-1; MMT-8, manual muscle testing-8; 6 MWD, 6 minute walking test distance; NA, not applicable; SF-36 PCS , short-form- 36 physical component summary.
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To cite this abstract in AMA style:
Witczak BN, Godang K, Bollerslev J, Schwartz T, Flatø B, Sjaastad I, Sanner H. Body Composition and Myokine Levels in Juvenile Dermatomyositis and Associations with Physical Function [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/body-composition-and-myokine-levels-in-juvenile-dermatomyositis-and-associations-with-physical-function/. Accessed .« Back to 2017 ACR/ARHP Annual Meeting
ACR Meeting Abstracts - https://acrabstracts.org/abstract/body-composition-and-myokine-levels-in-juvenile-dermatomyositis-and-associations-with-physical-function/