title: Bone marrow fat content in the elderly: a reversal of sex difference seen in younger subjects.
abstract: OBJECTIVE
  To investigate vertebral bone marrow fat content in elderly subjects related to sex, age, and bone mineral density (BMD) and relate these findings to published data in younger subjects.
  
  
  METHODS
  A total of 259 healthy subjects (145 females, 114 males; age range, 62-90 years) underwent proton ((1) H) MR spectroscopy of L3 vertebral body and BMD of the lumbar spine with results stratified according to age. Ninety age- and BMD-matched subjects were selected to determine sex differences in marrow fat content and BMD.
  
  
  RESULTS
  In females, vertebral marrow fat content rose sharply between 55 and 65 years of age while in males vertebral marrow fat content rose gradually throughout life. Vertebral marrow fat content in females more than 60 years was approximately 10% higher in females than males, i.e., a reversal of sex difference reported in marrow fat content for subjects less than 60 years.
  
  
  CONCLUSIONS
  Marrow fat content increases sharply in female subjects between 55 and 65 years of age while male subjects continue to increase marrow fat at a more gradual steady rate. Females older than 60 years have a higher marrow fat content than males. This increased deposition in marrow fat concurs with recognized changes in extraosseous fat distribution in postmenopausal females.
authors.affiliation: Department of Imaging and Interventional Radiology, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, NT, Hong Kong. griffith@cuhk.edu.hk
authors.forename: James F
authors.initials: JF
authors.lastname: Griffith
authors.forename: David K W
authors.initials: DK
authors.lastname: Yeung
authors.forename: Heather Ting
authors.initials: HT
authors.lastname: Ma
authors.forename: Jason Chi Shun
authors.initials: JC
authors.lastname: Leung
authors.forename: Timothy C Y
authors.initials: TC
authors.lastname: Kwok
authors.forename: Ping Chung
authors.initials: PC
authors.lastname: Leung
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology / Q000502:physiology*; D050154:Adiposity / Q000502:physiology*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology / Q000502:physiology*; D015519:Bone Density / Q000502:physiology*; D001853:Bone Marrow / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D017678:Sex Distribution; D012737:Sex Factors