title: Bone marrow fat unsaturation in young adults is not affected by present or childhood obesity, but increases with age: A pilot study.
abstract: OBJECTIVE
  Obesity increases bone marrow fat (BMF) content. The association between early obesity and bone marrow fatty acid composition is unknown. We measured BMF unsaturation index (UI) in normal-weight and overweight young adults with a known weight status in early childhood and tested the relationship between BMF UI and exercise history, glycemic state, and other clinical characteristics.
  
  
  METHODS
  The study included 18 normal-weight (BMI <25 kg/m(2); 2 males, 16 females) and 17 overweight (BMI ≥25 kg/m(2); 9 males, 8 females) young adults aged 15-27 years. BMF UI was assessed with magnetic resonance proton spectroscopy optimized to reduce water interference. Exercise information was obtained with a pedometer accompanied with the history of recent physical activity. Blood samples (insulin, glucose, HbA1c) and body characteristics (BMI, waist-to-hip ratio, body fat composition) were assessed.
  
  
  RESULTS
  BMF UI was not affected by obesity at the time of study or before age 7 years. BMF UI increased with age in normal-weight and overweight subjects (R=0.408, p=0.015) but did not associate with gender, physical activity or body fat composition; a suggestive association was observed with glucose (R=-0.289, p=0.10).
  
  
  CONCLUSIONS
  The association of BMF UI with age in early adulthood may represent normal maturation of bone marrow. There was a trend toward an association with blood glucose, warranting further studies.
authors.affiliation: Turku PET Centre, University of Turku, Turku, Finland; Department of Radiology, Turku University, Medical Imaging Centre of Southwest Finland and Turku University Hospital, Helsinki, Finland.
authors.forename: Ville
authors.initials: V
authors.lastname: Huovinen
authors.affiliation: Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland.
authors.forename: Heli
authors.initials: H
authors.lastname: Viljakainen
authors.affiliation: HUS Medical Imaging Center, Radiology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Hakkarainen
authors.affiliation: Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland; Novo Nordisk Farma Oy, Espoo, Finland.
authors.forename: Tero
authors.initials: T
authors.lastname: Saukkonen
authors.affiliation: HUS Medical Imaging Center, Radiology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.
authors.forename: Sanna
authors.initials: S
authors.lastname: Toiviainen-Salo
authors.affiliation: HUS Medical Imaging Center, Radiology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland.
authors.forename: Nina
authors.initials: N
authors.lastname: Lundbom
authors.affiliation: HUS Medical Imaging Center, Radiology, Helsinki University Central Hospital, University of Helsinki, Helsinki, Finland; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany; German Center for Diabetes Research, Partner Düsseldorf, Düsseldorf, Germany.
authors.forename: Jesper
authors.initials: J
authors.lastname: Lundbom
authors.affiliation: Children's Hospital, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland; Folkhälsan Institute of Genetics, Helsinki, Finland; Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden; Department of Molecular Medicine and Surgery, and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden. Electronic address: outi.makitie@helsinki.fi.
authors.forename: Outi
authors.initials: O
authors.lastname: Mäkitie
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D000375:Aging / Q000473:pathology*; D001853:Bone Marrow / Q000473:pathology*; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000473:pathology*; D010865:Pilot Projects; D055815:Young Adult
keywords: Bone marrow fat; Fatty acid composition; Obesity; Spectroscopy; Unsaturation