title: Circulating sclerostin associated with vertebral bone marrow fat in older men but not women.
abstract: BACKGROUND
  Osteocyte activity is crucial to the maintenance of bone quality. Sclerostin, an osteocyte product, inhibits bone formation, yet higher circulating sclerostin is associated with higher bone density. Bone marrow fat (MF) is associated with osteoporosis, but little is known about the relationship between osteocyte activity and MF.
  
  
  OBJECTIVE
  Our objective was to assess the relationships between circulating sclerostin, vertebral MF, volumetric bone mineral density (vBMD), and other fat depots in older adults.
  
  
  METHODS
  We conducted a cross-sectional study in the Age Gene/Environment Susceptibility-Reykjavik cohort.
  
  
  METHODS
  Outcome measures included vertebral MF (L1-L4) measured with magnetic resonance spectroscopy and vBMD (spine and hip) and abdominal fat measured with quantitative computed tomography.
  
  
  RESULTS
  After excluding subjects with bone-active medication use (n = 50), inadequate serum (n = 2), or inadequate magnetic resonance spectroscopy (n = 1), analyses included 115 men and 134 women (mean age 79 y, mean body mass index 27.7 kg/m(2)). In men, but not women, vertebral MF was greater in those with higher serum sclerostin levels. MF was 52.2 % in the lowest tertile of serum sclerostin and 56.3% in the highest tertile in men (P for trend <.01) in models adjusted for age, body mass index, and diabetes. Sclerostin was positively associated with cortical and trabecular total hip vBMD, weight in men and women, and total fat mass in men but was not associated with total lean mass or abdominal fat depots.
  
  
  CONCLUSIONS
  Circulating sclerostin levels are associated with higher vertebral marrow fat in men, suggesting a relationship between osteocyte function and marrow adipogenesis.
authors.affiliation: University of California, San Francisco (Y.-H.V.M., A.V.S., T.F.H., T.F.L., E.V., L.P., X.L.), San Francisco, California 94107; Icelandic Heart Association (S.S., G.E., A.M.H., K.S., D.O., V.G.), IS-201 Kopavogur, Iceland; Laboratory of Epidemiology, Demography, and Biometry (T.B.H.), Intramural Research Program, National Institute on Aging, Bethesda, Maryland 20892; Maine Medical Center Research Institute (C.J.R.), Scarborough, Maine 04074; Faculty of Medicine (G.S., D.O., V.G.), University of Iceland, IS-101 Reykjavik, Iceland; Department of Endocrinology and Metabolism (G.S.), Landspitali University Hospital, IS-101 Reykjavik, Iceland; and Universita Campus Bio-Medico (N.N.), 00128 Rome, Italy.
authors.forename: Yu-Heng Vivian
authors.initials: YH
authors.lastname: Ma
authors.forename: Ann V
authors.initials: AV
authors.lastname: Schwartz
authors.forename: Sigurdur
authors.initials: S
authors.lastname: Sigurdsson
authors.forename: Trisha F
authors.initials: TF
authors.lastname: Hue
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Lang
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Rosen
authors.forename: Eric
authors.initials: E
authors.lastname: Vittinghoff
authors.forename: Gudny
authors.initials: G
authors.lastname: Eiriksdottir
authors.forename: Alda M
authors.initials: AM
authors.lastname: Hauksdottir
authors.forename: Kristin
authors.initials: K
authors.lastname: Siggeirsdottir
authors.forename: Gunnar
authors.initials: G
authors.lastname: Sigurdsson
authors.forename: Diana
authors.initials: D
authors.lastname: Oskarsdottir
authors.forename: Nicola
authors.initials: N
authors.lastname: Napoli
authors.forename: Lisa
authors.initials: L
authors.lastname: Palermo
authors.forename: Vilmundur
authors.initials: V
authors.lastname: Gudnason
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Li
mesh_terms: D015502:Absorptiometry, Photon; D048868:Adaptor Proteins, Signal Transducing; D000273:Adipose Tissue / Q000378:metabolism*; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D015519:Bone Density / Q000502:physiology; D001853:Bone Marrow / Q000378:metabolism*; D019485:Bone Morphogenetic Proteins / Q000097:blood*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005819:Genetic Markers; D006801:Humans; D007055:Iceland / Q000453:epidemiology; D008297:Male; D010011:Osteocytes / Q000502:physiology; D010024:Osteoporosis / Q000453:epidemiology; D012727:Sex Characteristics; D014057:Tomography, X-Ray Computed
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015415:Biomarkers; D019485:Bone Morphogenetic Proteins; D005819:Genetic Markers; C422903:SOST protein, human