title: Decreased nocturnal oxytocin levels in anorexia nervosa are associated with low bone mineral density and fat mass.
abstract: OBJECTIVE
  Anorexia nervosa is characterized by self-induced starvation and associated with severe bone and fat loss. Oxytocin is a peptide hormone involved in appetite and energy homeostasis. Recent data show that oxytocin has an anabolic effect on bone and stimulates osteoblast function. There is limited information about oxytocin levels or their relationship to decreased bone mineral density in anorexia nervosa. Our objective was to investigate the relationship between oxytocin levels, bone mineral density, and body composition in women with anorexia nervosa.
  
  
  METHODS
  We studied 36 women, mean ± SEM age 27.6 ± 1.3 years: 17 with DSM-IV anorexia nervosa and 19 healthy controls in a cross-sectional study. Oxytocin levels were determined from pooled serum samples obtained every 20 minutes from 8 pm to 8 am during an inpatient overnight visit. Fasting leptin levels were measured. Bone mineral density at the anterior-posterior and lateral spine and hip and body composition were assessed by dual energy x-ray absorptiometry. The study was conducted from September 2004 to June 2008.
  
  
  RESULTS
  Subjects with anorexia nervosa versus healthy controls had lower mean ± SEM oxytocin levels (14.3 ± 1.5 vs 31.8 ± 5.1 pg/mL, P = .003), leptin levels (2.7 ± 0.5 vs 11.4 ± 1.1 ng/mL, P < .0001), bone mineral density (anterior-posterior spine: 0.83 ± 0.02 vs 1.04 ± 0.03; lateral spine: 0.63 ± 0.02 vs 0.81 ± 0.02; total hip: 0.79 ± 0.03 vs 0.97 ± 0.03 g/cm², P < .0001), and fat mass (8.8 ± 0.6 vs 19.7 ± 0.9 kg, P < .0001). Oxytocin levels were associated with bone mineral density at the anterior-posterior (r = 0.40, P = .02) and lateral (r = 0.36, P = .04) spine, fat mass (r = 0.42, P = .01), and leptin levels (r = 0.55, P = .001).
  
  
  CONCLUSIONS
  Overnight secretion of oxytocin in women with anorexia nervosa is decreased compared with healthy women. Low oxytocin levels are associated with decreased bone mineral density and body fat and may contribute to anorexia nervosa-induced bone loss.
authors: Neuroendocrine Unit, Bulfinch 457B, Massachusetts General Hospital, Boston, MA 02114, USA. ealawson@partners.org
authors: Elizabeth A
authors: EA
authors: Lawson
authors: Daniel A
authors: DA
authors: Donoho
authors: Justine I
authors: JI
authors: Blum
authors: Erinne M
authors: EM
authors: Meenaghan
authors: Madhusmita
authors: M
authors: Misra
authors: David B
authors: DB
authors: Herzog
authors: Patrick M
authors: PM
authors: Sluss
authors: Karen K
authors: KK
authors: Miller
authors: Anne
authors: A
authors: Klibanski
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism / Q000473:pathology*; D000328:Adult; D000856:Anorexia Nervosa / Q000150:complications* / Q000378:metabolism; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D010121:Oxytocin / Q000096:biosynthesis / Q000172:deficiency* / Q000378:metabolism
chemical_list: D010121:Oxytocin