title: Body composition phenotypes in systemic lupus erythematosus and rheumatoid arthritis: a comparative study of Caucasian female patients.
abstract: OBJECTIVE
  The amount and distribution of fat and lean mass have important implications for health and systemic inflammation may represent a risk for altered body composition. The aim of this study was to analyse whether changes in body composition are similarly associated with systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA), two inflammatory conditions of different pathogenesis.
  
  
  METHODS
  Body mass index (BMI), waist circumference, fat mass (FM) and fat-free mass (FFM) were measured in 92 women with SLE, 89 with RA and 107 controls. Results were compared among the 3 groups and correlations of FM percentage were explored within SLE and RA.
  
  
  RESULTS
  Abnormal body composition was more frequent in women with SLE and RA than in non-inflammatory controls, despite having a similar BMI. RA diagnosis was significantly associated with overfat (OR=2.782, 95%CI 1.470-5.264; p=0.002) and central obesity (OR=2.998, 95%CI 1.016-8.841; p=0.04), while sarcopenia was more common among SLE (OR=3.003; 95%CI 1.178-7.676; p=0.01). Sarcopenic obesity, i.e. the coexistence of overfat with sarcopenia, was present in 6.5% of SLE and 5.6% of RA women, but no controls. Independent correlations of FM percentage in women with SLE included smoking, disease activity and CRP. In RA, education, disease activity and cumulative corticosteroid dose were identified as independent predictors of FM percentage.
  
  
  CONCLUSIONS
  Women with SLE or RA diagnosis are more likely to have abnormal body composition phenotype, with some differences existing between these two conditions. Changes in body composition are partly explained by the inflammatory burden of disease and its treatment.
authors.affiliation: Rheumatology Research Unit, Instituto de Medicina Molecular da Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal. mjps@netvisao.pt
authors.forename: M J
authors.initials: MJ
authors.lastname: Santos
authors.forename: F
authors.initials: F
authors.lastname: Vinagre
authors.forename: J
authors.initials: J
authors.lastname: Canas da Silva
authors.forename: V
authors.initials: V
authors.lastname: Gil
authors.forename: J E
authors.initials: JE
authors.lastname: Fonseca
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000503:physiopathology*; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D005260:Female; D006801:Humans; D015994:Incidence; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000503:physiopathology*; D008875:Middle Aged; D056128:Obesity, Abdominal / Q000453:epidemiology; D010641:Phenotype; D012307:Risk Factors; D055948:Sarcopenia / Q000453:epidemiology; D055105:Waist Circumference / Q000502:physiology; D044465:White People