title: Low muscle mass and sarcopenia: common and predictive of osteopenia in inflammatory bowel disease.
abstract: BACKGROUND
  Body composition is poorly studied in inflammatory bowel disease (IBD). Sarcopenia describes a loss of muscle mass and strength.
  
  
  OBJECTIVE
  To assess the prevalence of low lean mass (LM), sarcopenia and associated morbidity in an adult IBD cohort.
  
  
  METHODS
  Cross-sectional data were gathered on pre-menopausal 18- to 50-year-old patients with IBD. Whole-body dual-energy X-ray absorptiometry, anthropometric assessment and grip strength were performed. Low LM was defined as ≥1 s.d. below the population mean for appendicular skeletal muscle index [ASMI (kg)/height (m)²], and sarcopenia as both ASMI and grip strength ≥1 s.d. below population mean. Multivariate regression analyses were performed.
  
  
  RESULTS
  Of 137 participants (median age 31 years, BMI 24.8 kg/m(2) ), 56% were male and 69% had Crohn's disease (CD). Low LM and sarcopenia were observed in 21% and 12% of patients, respectively, and osteopenia/osteoporosis in 38% of patients (mean lumbar spine t-score -0.3 ± s.d. 1.1). Grip strength predicted low LM and sarcopenia better than did body mass index (BMI) (OR 4.8 vs. OR 0.7 for low-LM, P < 0.05 both). Normal BMI was falsely reassuring in 72% and 76% of patients with low ASMI and sarcopenia, respectively. Low LM and sarcopenia (OR = 3.6, P = 0.03; OR = 6.3, P = 0.02; respectively), but not BMI nor fat mass, predicted osteopenia/osteoporosis.
  
  
  CONCLUSIONS
  Low lean mass and sarcopenia are common in patients with IBD, and important to recognise as they predict osteopenia/osteoporosis. Grip strength testing should be incorporated into routine clinical practice to detect low lean mass deficits, which may go unrecognised using BMI alone.
authors.affiliation: Inflammatory Bowel Disease Service, Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, SA, Australia; School of Medicine, University of Adelaide, Adelaide, SA, Australia.
authors.forename: R V
authors.initials: RV
authors.lastname: Bryant
authors.forename: S
authors.initials: S
authors.lastname: Ooi
authors.forename: C G
authors.initials: CG
authors.lastname: Schultz
authors.forename: C
authors.initials: C
authors.lastname: Goess
authors.forename: R
authors.initials: R
authors.lastname: Grafton
authors.forename: J
authors.initials: J
authors.lastname: Hughes
authors.forename: A
authors.initials: A
authors.lastname: Lim
authors.forename: F D
authors.initials: FD
authors.lastname: Bartholomeusz
authors.forename: J M
authors.initials: JM
authors.lastname: Andrews
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000886:Anthropometry; D001823:Body Composition / Q000502:physiology; D015992:Body Mass Index; D001851:Bone Diseases, Metabolic / Q000453:epidemiology*; D003424:Crohn Disease / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000503:physiopathology*; D008297:Male; D010024:Osteoporosis / Q000453:epidemiology*; D015995:Prevalence; D055948:Sarcopenia / Q000453:epidemiology*; D055815:Young Adult