Pos1152 bone and muscle impairment and higher visceral adipose tissue mass in women with long-term polyarticular juvenil idiopathic arthritis

Background Some studies suggest that patients with juvenile idiopathic arthritis (JIA) may have reduced bone parameters and muscle mass. Despite those considerations, there is no validated consensus about this topic in the literature as the population and the methods for bone and muscle evaluation are often heterogeneous and not standardized. Objectives To assess bone parameters and body composition of women with long-term polyarticular JIA and compare them to healthy controls. Methods Twenty-seven women with long-term polyarticular JIA were compared with twenty-seven healthy controls, matched by sex, age, and body mass index (BMI). Dual-energy X-ray absorptiometry (DXA) was performed to evaluate the lean mass, body fat percentage (% Fat), and visceral adipose tissue mass (VATm). High resolution peripheral quantitative computed tomography (HR-pQCT) at the distal radius and tibia was performed to assess trabecular (Tb.) and cortical (Ct.) volumetric bone mineral density (v.BMD) and strength bone parameters (stiffness - S; estimated fail load - FL). Group means were compared using Student’s t-test. Results Polyarticular JIA patients have a lower trabecular and cortical volumetric bone density, a lower bone strength, and a lower lean mass compared to healthy controls. Moreover, long-term JIA patients have a higher visceral adipose tissue mass (Table 1). Table 1. Bone parameters using high resolution peripheral quantitative computed tomography (HR-pQCT) and body composition in long-term polyarticular patients and healthy controls. Polyarticular JIA n=27 Healthy controls n=27 p-value Age, years 31.8 ± 7.6 33 ± 8.2 0.597 BMI, Kg/m 2 24 ± 4.8 24.6 ± 4.7 0.931 Disease duration, years 22 ± 10 ----- Remission or low activity, n (% ) 16 (59) ----- Use of prednisone, n (% ) 5 (18) ----- Rheumatoid factor 9 (33) 0 (0) Lean mass, kg 35.7 ± 4.7 39 ± 7.2 <0.001 %Fat, % 39 ± 8 37 ± 7 0.364 VATm, kg 588 ± 538 212 ± 209 0.001 HR-pQCT at the distal radius Tb.v.BMD, mg HA/cm 3 125 ± 32 159 ± 38 <0.001 Ct.v.BMD, mg HA/cm 3 994 ± 46 1035 ± 43 <0.001 S, kN/mm 64 ± 11 78 ± 18 0.001 FL, N 3174 ± 879 3710 ± 827 <0.001 HR-pQCT at the distal tibia Tb.vBMD, mg HA/cm 3 128 ± 48 162 ± 32 0.003 Ct.vBMD, mg HA/cm 3 990 ± 57 993 ± 52 0.811 S, kN/mm 179 ± 39 212 ± 40 <0.001 FL, N 8519 ± 1773 9675 ± 2525 0.004 Data expressed as mean ± standard deviation or frequency (percentage). Tb.vBMD – trabecular volumetric bone mineral density, Ct.vBMD – cortical volumetric bone mineral density; S - stiffness; FL - estimated fail load Conclusion Pre-menopausal women with long-term polyarticular JIA have an impairment of bone mineral density at peripheral sites in addition to lower muscle mass and higher visceral adipose tissue. These findings may contribute to the increasing osteoporosis/fractures and cardiovascular risk in this population, suggesting that measures should be considered to prevent these damages. References [1]Bechtold S, Ripperger P, Dalla Pozza R, Schmidt H, Häfner R, Schwarz HP. Musculoskeletal and functional muscle-bone analysis in children with rheumatic disease using peripheral quantitative computed tomography. Osteoporos Int a J Establ as result Coop between Eur Found Osteoporos Natl Osteoporos Found USA. 2005 Jul;16(7):757–63. [2]Burnham JM, Shults J, Sembhi H, Zemel BS, Leonard MB. The dysfunctional muscle-bone unit in juvenile idiopathic arthritis. J Musculoskelet Neuronal Interact. 2006;6(4):351–2. [3]Felin EMO, Prahalad S, Askew EW, Moyer-Mileur LJ. Musculoskeletal abnormalities of the tibia in juvenile rheumatoid arthritis. Arthritis Rheum. 2007 Mar;56(3):984–94. [4]Roth J, Linge M, Tzaribachev N, Schweizer R, Kuemmerle-Deschner J. Musculoskeletal abnormalities in juvenile idiopathic arthritis - A 4-year longitudinal study. Rheumatology. 2007 Jul;46(7):1180–4.5. Disclosure of Interests None declared