Background:Fibrosis of the skin and visceral organs, especially digestive tract, and musculoskeletal involvement in systemic sclerosis (SSc) can have a negative impact on body composition, physical activity and nutritional status.Objectives:The aim was to assess body composition and physical activity of SSc patients and healthy controls (HC) and the association with selected inflammatory cytokines/chemokines and laboratory markers of nutritional status and lipid metabolism in SSc.Methods:59 patients with SSc (50 females; mean age 52.5; disease duration 6.7 years; lcSSc: 34/dcSSc: 25) and 59 age-/sex-matched HC (50 females, mean age 52.5) without rheumatic or tumour diseases were included. SSc patients fulfilled ACR/EULAR 2013 criteria. We assessed body composition (densitometry: iDXA Lunar, bioelectric impedance: BIA-2000-M), physical activity (Human Activity Profile, HAP questionnaire), disease activity (ESSG activity index), serum levels of 27 cytokines/chemokines (commercial multiplex ELISA kit, Bio-Rad Laboratories) and serum levels of chosen parameters of nutrition and lipidogram. Data are presented as mean±SD.Results:Compared to HC, patients with SSc had significantly lower body mass index (BMI, 27.4±8.3 vs. 22.4±4.3 kg/m2, p<0,001), body fat % (BF%, iDXA: 38.0±7.6 vs. 32.6±8.2 kg, p<0,001; BIA: 31.3±7.6 vs. 24.3±7.9 kg, p<0,001) and visceral fat weight (VF, 1.0±0.8 vs. 0.5±0.5 kg, p=0,001), and also significantly decreased lean body mass (LBM, iDXA: 51.9±8.4 vs. 47.8±7.0 kg, p=0,005; BIA: 45.4±7.3 vs. 40.9±6.8 kg, p=0,005), and bone mineral density (BMD, 1.2±0.1 vs. 1.0±0.1 g/cm2, p<0,001). Compared to HC, patients with SSc had increased extracellular mass/body cell mass (ECM/BCM, 1.03±0.1 vs. 1.28±0.4, p<0,001) ratio, reflecting deteriorated nutritional status and worse muscle predispositions for physical activity. Increased ECM/BCM in SSc was associated with higher disease activity (ESSG), increased skin score (mRSS) and inflammation (CRP, ESR), and with worse quality of life (HAQ, SHAQ), fatigue (FSS), and decreased physical activity (HAP). ESSG negatively correlated with BF%. HAP positively correlated with BMD. Serum levels of several inflammatory cytokines/chemokines (specifically IL-1b, IL-5, IL-6, IL-8, IL-17, TNF, Eotaxin) and markers of nutrition (specifically total protein, albumin, insulin and C-peptide) and lipid metabolism (specifically triglycerides, high-density lipoprotein, apolipoprotein A, atherogenic index of plasma) were significantly associated with alterations of body composition in patients with SSc (p<0.05 for all correlations).Conclusion:Compared to healthy age-/sex-matched individuals we found significant negative changes in body composition of our SSc patients, which are associated with the disease activity and physical activity, and could reflect their nutritional status, and gastrointestinal and musculoskeletal involvement. Detected alterations of body composition in SSc patients were significantly associated with serum levels of several inflammatory cytokines/chemokines and markers of nutrition and lipid metabolism, which might further support the role of systemic inflammation and nutritional status on the negative changes in body composition of SSc patientsAcknowledgments:Supported by AZV NV18-01-00161A, MHCR 023728, SVV 260373 and GAUK 312218Disclosure of Interests:Sabina Oreska: None declared, Maja Špiritović: None declared, Petr Česák: None declared, Michal Cesak: None declared, Hana Štorkánová: None declared, Hana Smucrova: None declared, Barbora Heřmánková: None declared, Olga Růžičková: None declared, Heřman Mann: None declared, Karel Pavelka Consultant of: Abbvie, MSD, BMS, Egis, Roche, UCB, Medac, Pfizer, Biogen, Speakers bureau: Abbvie, MSD, BMS, Egis, Roche, UCB, Medac, Pfizer, Biogen, Ladislav Šenolt: None declared, Jiří Vencovský: None declared, Radim Bečvář Consultant of: Actelion, Roche, Michal Tomčík: None declared