Objectives: Systemic inflammation, corticosteroid therapy, and reduced physical activity are risk factors for altered body composition in patients with systemic lupus erythematosus (SLE). The aim of this study was to assess whether body composition differs between childhood-onset SLE patients and healthy controls, and to investigate the impact of disease characteristics and lifestyle factors on body fat mass, serum lipids, and lipoproteins.
Methods: Fat mass and lean tissue mass were measured in a cross-sectional study of 68 childhood-onset SLE patients and 68 matched healthy controls by dual-energy X-ray absorptiometry (DXA). The influence of disease, glucocorticosteroids, disease activity and severity, physical activity, and dietary intake on fat mass was evaluated by multiple linear regression analysis. Serum lipid and lipoprotein levels were measured.
Results: Patients had a significantly higher fat mass [mean (SD) 35.3 (10.8) vs. 30.9 (11.1)%; p = 0.024] and lower lean mass [39.7 (9.8) vs. 44.4 (1.5) kg; p = 0.003] than controls. Corticosteroid use and the disease itself were significant independent predictors of greater fat mass, while disease activity, physical activity, and dietary intake had only a minor influence. Mean high density lipoprotein (HDL) cholesterol and apolipoprotein A1 (apo A1) levels were significantly lower (p<0.001), and the mean apo B/apo A1 ratio significantly higher (p = 0.004), in patients than in controls.
Conclusion: Childhood-onset SLE patients had a higher fat mass and lower lean mass than healthy controls and corticosteroid use was an independent predictor of increased fat mass. Patients had a more proatherogenic lipid profile, which will contribute to the increased risk of coronary heart disease in SLE patients.