title: Assessment of Sex Differences in Body Composition Among Adolescents With Anorexia Nervosa.
abstract: OBJECTIVE
  To compare deficits in fat mass (FM) and lean body mass (LM) among male and female adolescents with anorexia nervosa (AN) and to identify other covariates associated with body composition.
  
  
  METHODS
  We retrospectively reviewed electronic medical records of all subjects aged 9-20 years with a Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition diagnosis of AN and dual-energy x-ray absorptiometry scans after initial evaluation at Stanford between March 1997 and February 2011. From the dual-energy x-ray absorptiometry scans, LM and FM results were converted to age-, height-, sex-, and race-specific Z-scores for age using the National Health and Nutrition Examination Survey reference data.
  
  
  RESULTS
  A total of 16 boys and 119 girls with AN met eligibility criteria. The FM Z-score in girls with AN (-3.24 ± 1.50) was significantly lower than that in boys with AN (-2.41 ± .96) in unadjusted models (p = .007). LM was reduced in both girls and boys with AN, but there was no significant sex difference in LM Z-scores. In multivariate models, lower percentage median body mass index was significantly associated with lower FM Z-scores (β = .08, p < .0001) and lower LM Z-score (β = .03, p = .0002), whereas lower whole body bone mineral content Z-score was significantly associated with lower LM Z-score (β = .21, p = .0006).
  
  
  CONCLUSIONS
  FM deficits in girls were significantly greater than those in boys with AN in unadjusted models; however, the degree of malnutrition appeared to be the primary factor accounting for this difference. There were no significant sex differences in FM or LM in adjusted models.
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California; Department of Pediatrics, Division of Adolescent and Young Adult Medicine, University of California, San Francisco, San Francisco, California. Electronic address: jasonmnagata@gmail.com.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Nagata
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California.
authors.forename: Neville H
authors.initials: NH
authors.lastname: Golden
authors.affiliation: Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
authors.forename: Rebecka
authors.initials: R
authors.lastname: Peebles
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California.
authors.forename: Jin
authors.initials: J
authors.lastname: Long
authors.affiliation: Department of Psychiatry, University of California, San Francisco, San Francisco, California.
authors.forename: Stuart B
authors.initials: SB
authors.lastname: Murray
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California.
authors.forename: Mary B
authors.initials: MB
authors.lastname: Leonard
authors.affiliation: Department of Pediatrics, Stanford University School of Medicine, Palo Alto, California.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Carlson
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000856:Anorexia Nervosa / Q000145:classification / Q000150:complications* / Q000175:diagnosis; D001823:Body Composition; D050218:Body Fat Distribution; D015992:Body Mass Index; D002140:California; D002648:Child; D039721:Diagnostic and Statistical Manual of Mental Disorders; D057286:Electronic Health Records / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D044342:Malnutrition / Q000209:etiology* / Q000503:physiopathology; D012189:Retrospective Studies; D012737:Sex Factors; D055815:Young Adult
keywords: Anorexia nervosa; Body composition; Dual-energy x-ray absorptiometry; Eating disorders; Females; Males; Sex differences